This has come up on the Paizo boards before but as far as I am aware no one has finished their work.
Short answer is there's no easy way to do it, but you should be able to take the suggestions in the Conversion Guide for converting the core classes and apply it to the generic classes as presented on the d20 SRD.
The generic modifications (Hit Die, saves, etc) are going to be fairly trivial, the hard part is going to be selecting which class features you'd allow as "feats". If you are interested in going that route, I would suggest you start with some of the abilities from Fighter, Monk, Sorcerer (from the "default" bloodline), and Cleric and add some of the class features from those. But there's no "correct" way to do that. You also need to remember that Pathfinder has a tendency to ramp the power levels of all classes, bonus feats, class abilities, etc, so that needs to play a factor in your conversion.
Alternatively, and I almost prefer this suggestion, is to take the NPC classes presented in the Pathfinder Core book, and modify them to have PC BAB, Saves, and other class features. So, for example you'd be playing an Adept with a higher BAB, and better Saves (probably following the Cleric Progression), but with Adept abilities and spell lists. You'd have to expand their abilities further on if you plan on playing a long time like that...
So, yeah, no easy answer, hopefully this will help give you some ideas.
Combat is measured in rounds. A round is 6 seconds. Note that this is not the length of a turn, but the length of a round: everyone’s turns are happening near-simultaneously, with just a slight edge to those who have higher initiative.
So there are 10 rounds to a minute, and then of course there are 60 minutes (600 rounds) to an hour, and 24 hours (1,440 minutes or 14,400 rounds) to a day.
More importantly, the general guideline is for there to be four encounters in a typical day, and each should exhaust roughly 20% of the party’s daily resources (leaving a 20% margin of error/leeway for more challenging days/allowance for recuperation for the next day). How much time takes place between these is generally a matter of plot, and of course there are lots of ways you can do things differently (more but easier fights, fewer but more dangerous fights, etc.). And, of course, this is just the guideline; you can’t do the same thing every day and still keep things interesting. An important part of DMing is knowing when and how to flout such guidelines for the sake of improving the game.
Note also that players have a fair amount of control over when and where they will go places. A wizard is probably only going to be willing to venture into the dark ‘n’ scary dungeon (a technical term) when he’s out of spell slots if things are truly dire and urgent; otherwise he’s going to be strongly pushing for the group to stop and rest. Same with a fighter who’s running low on health, or what have you.
A Note on Spells Per Day
Worth noting: arcane and divine spellcasters have different rules for defining a “day” in terms of when they get their spells back.
For divine spellcasters, they simply have a particular hour in which they are supposed to be praying – clerics of a sun god might pray at dawn, or high noon, while a druid of the twilight lady of the forest (a deity I just now made up) would likely pray at dusk. Unlike arcanists, divine spellcasters do not require sleep to refresh their spells.
On the arcane side, they can prepare/refresh spell slots at any time of day, but must get eight straight hours of sleep (there are rules for interrupted sleep and how that affects getting to refresh) between refreshes. Strictly speaking, there is nothing that prevents an arcane caster from blowing all his spells in one fight, and immediately go back to sleep and refresh again. That’s frowned upon by... almost every gaming table ever, for obvious reasons, though. Most groups expect one 8-hour rest per 24-hour day, which means the differences between arcane and divine casters don’t see a lot of play in practice. At the same time, the average Wizard, in particular, will push for about 17 hours of downtime per day: 8 hours of sleep and 1 hour of spell preparation are mandatory, and then 8 hours of time for crafting or scribing spells in his spellbook are going to be considered highly desirable (as in, he’s going to want to have that kind of time more often than not). Of course, plot may dictate that he cannot have that kind of time, but if matters aren’t urgent those are a wizard’s natural inclinations.
Anyway, despite the detail that the rules provide for these things, almost all groups I’ve played with have not paid such close attention to timing. Unless the DM specifically ambushed the group at night, or that time (as in a matter of hours) was of critical importance, these issues were hand-waved away and spellcasters simply started every day with whatever spells, which refreshed whenever the group decided to stop and make camp.
A Note on Spell Durations
From a player’s standpoint, spells generally come in only a few durations:
“right now” – Stuff with a duration of 1 round, Instantaneous damage spells, etc. At very-low levels, also includes rounds/level spells.
“this encounter” – Anything that has a duration from about thirty seconds to a few minutes (roughly 5-100 rounds). These are usually too short to cast before combat starts, but usually last long enough to see the current encounter finished. Stuff measured in rounds/level usually falls here, and minutes/level often does too unless you’re very high level or you have reason to expect a fight soon.
“through the next encounter” – Basically, anything that you feel you can cast ahead of time and still have available through the next encounter. How long is required for that depends heavily on circumstances; if you know there are monsters all over the place, you may only need a few minutes, but if you're walking down a road you might want a couple of hours. At very low levels, hours/level spells are the main sort available for this, but by mid levels spells that have durations like “10 minutes/level” will fit the bill most of the time. In that crowded dungeon, 1 minute/level may be sufficient.
“All day” – Stuff you can cast at the beginning of the day and forget about. By mid-levels, hours/level will cover this (8 hours will cover a full day for a lot of parties, dividing the day into thirds between adventuring, downtime, and sleeping). Obviously, anything that lists 24 hours as a duration also qualifies.
“Multiple days” – Stuff you don’t need to cast every day to continue to benefit from it. There aren’t many spells with durations of days/level, but they do exist. More significantly, Permanent effects and also some things with a duration of Instantaneous (when they create something or provide a lasting benefit) go in this category.
As a DM, you will probably want to keep these ideas in mind when planning encounters – consider the spells that a party can expect to have already-running when they start a fight. Buffs that you don’t have to spend actions in combat on are automatically much better than buffs that require time during the fight. The only time I recommend paying careful attention to a spell’s duration is when a player casts a spell that is borderline between “this encounter” and “through the next encounter” – it can make a big difference whether or not that spell is still in play during the next encounter.
Best Answer
Don't worry about vocal characteristics (like accent and pitch); they'll be too hard to maintain over the long run, and will just annoy the other players.
Instead, show how your species is different in culture and mindset. Choose a normal human concept and break it, showing what your species does instead.
For example, let's say your species doesn't consider children to be sentient, full members of the species. But, your species considers adults' lives to be sacred, not to be lost for any reason. This will impact your responses to situations, thereby marking you as something different.
The party finds a child crying that their parents were killed by some kind of beast. You act surprised that the party is paying any heed to the babblings of a child. You assumed they would leave it alone wherever they found it, expecting it would probably die in the wilderness. After all, hatchlings without a nest have no chance to become adults.
The party finds out that some violent criminal they delivered to the king is due to be executed. You assume the party is now going to mount a rescue mission, no matter the cost to themselves.
What if your species considers anywhere they sleep to be their own territory while they're there?
The party is invited to spend the night at the home of the local earl. Understanding that this is the earl's way of inviting you to share in the ownership of the estate, you start asking about the financials of the place, wanting to know how much the servants are being paid, how much is being spent on the grounds, etc.
After the incident with the earl, you make sure to sleep outside whenever visiting a town, so as not to lay claim to anyone's home.
What if your species has no respect for dead bodies?
What if your species has no hesitation to give up their life when it would help the greater good (like with bees)?
The party is pinned down by a sniper that they haven't been able to find yet. You intend to walk right out into the open so the sniper can take their shot, expecting to die in the process, yet revealing their position to the party.
The party captures an enemy officer and begins questioning him about his army's movements. You're bewildered that he allowed himself to be captured instead of committing suicide so that his knowledge couldn't fall into the wrong hands.