So after some more experimenting I am pretty confident that experience overall is 50% (towards your character level) and Skill Experience is 75-80% for Lives that do not naturally have the Skill you are using. Interestingly enough crafting experience is not affected by the quality of the item you create. A Superior item nets you the same experience and skill experience as a normal one. EDIT: Combat skills below.
I will post the numbers I have later.
As a Blacksmith:
* "Good" Gold Pickaxe - 115 exp - 215 Smithing Exp
* "Good" Iron Sword - 25 exp - 71 Smithing Exp
* "Great" Iron Sword - 25 Exp - 71 Smithing Exp
As a Carpenter:
* Normal Gold Pickaxe - 57 Exp (50%) - 170 Smithing Exp (80%)
* "Great" Iron Sword - 12 Exp (50%) - 55 Smithing Exp (76%)
Combat Basic data. 33% Experience gain for a skill not naturally used by that Life.
As a Paladin:
* 3 hit combo on Pterodactyl - 15 Longsword Exp
* 2 Hits (one each on the sheep things in East Grassy Plains) - 6 exp
As a Mercenary:
* 3 Hit combo on Pterodactyl - 6 Longsword Exp (33%)
* 2 Hits (one each on the sheep things) - 2 exp (33%)
As a Blacksmith:
* 3 Hit combo on Angry Cactus - 6 Longsword Exp (33%)
Not sure how much more in depth I want to go. But I was very surprised how low the combat exp was for the wrong Life. And it looks like being a crafting job does not change the ratio.
The time used to catch the fish is not relevant because the fish is chosen by the game when you first pull your rod, hence the HP bar becomes easy or difficult to pull.
Each area has like 3-4 types of fish, and maybe two of then can be caught in giant size.
And to be better at fishing you just have to fish a lot and in tougher places, so you can level up faster.
Best Answer
This list is far too long to post as an answer, but there are some guidelines to follow if you want to make sure to be able to craft everything:
Talk to everyone with a question mark above their head, especially your life master. These are NPCs that are associated with one of the lives that you have begun, and talking to them occasionally rewards you with an item, recipe, or task. Sometimes this can be required to rank up! Other NPCs don't give out recipes as far as I know.
Revisit these NPCs when you rank up. Every time you rank up, the question marks will reappear above their head which means they have something new to say or give you. These stack, so talk to these NPCs until the question mark is gone. Since you won't lose anything and this process can take some time, you can wait a few ranks if you don't want to bother with it right away.
Enter every building in every town. This can be a tiresome process, but sometimes an NPC associated with your life is in a shop associated with a different life. If you do it enough, you will start to memorize where the NPCs are for your particular life and you won't need to waste time looking in places where you know they aren't.
Unfortunately, you can't get certain recipes until you reach the proper rank, so you can't just visit an NPC once and get everything you want from them. However, most of the time the rewards aren't essential (sometimes you get nothing), so you can usually wait until you're a master to run around and grab stuff from everybody.