Oracle is a spontaneous, divine spellcasting class. She has a greater number of spells per day than a Cleric, and can cast without preparing in advance; but, she has a narrower list of spells that she can choose from. She is the divine equivalent of a Sorcerer (whereas a Cleric is comparable to a divine Wizard).

Be mindful that Oracle isn't especially tuned for making ranged attacks (though she isn't terrible); as you level up, if you find that ranged attacks are your focus more than spells, you may want to consider multi-classing into a prestige class that gives you a higher Base Attack Bonus while continuing your spell progression (Eldritch Knight is a good example). On the other hand, you may decide that you want the Oracle's neat higher-level class abilities (Revelations, etc) more than you want a couple points of extra attack bonus.

Abilities:

Key ability: Cha.

Your key Ability score is Charisma, since Cha gives your spells a higher save DC, limits the highest level of spells you can cast, and grants you bonus spells per day.

For ranged combat, you also need a high Dex. Dex also improves your ability to dodge attacks, and increases your Reflex save (resist fireballs, traps, etc).

Con gets you more hit points, and a higher Fortitude save (resist poison, being turned to stone, etc).

Str won't be very important to your character, except to carry gear.

Int grants you more skill points.

Wis gives you a higher Will save (resist mind-affecting spells, etc).

Skills:

Look through the class skills to figure out what interests you. You should have max ranks in the Spellcraft skill. You can also choose cross-class skills without a big penalty in Pathfinder, so you should skim through the entire skill list to see what's available.

As a rule of thumb, I usually pick a number of skills equal to the number of skill ranks I get per level. For example, if you get 8 skill points per level, you could put max ranks in 8 different skills. If you decide you want more skills than that, you can split up one "ranked skill" into two "half-ranked" skills, and put a half-point in each every level. This isn't a hard-and-fast rule, just a way that I've found of making the decisions and the math much easier.

Feats:

The Extra Revelation feat is an Oracle-specific feat lets you choose an additional optional ability from the list for your chosen Mystery.

Since your character is heavily involved with ghosts, I think the Ectoplasmic Spell metamagic feat from Advanced Players' Guide would be appropriate.

Beyond that, feats which enhance your spellcasting will be the most effective for your character; since you are doing ranged combat, you will have to split your feats between ranged and spellcasting. I would recommend reading through the table at the beginning of the Feats chapter (both in the core rulebook and the Advanced Players' Guide) to get a brief description of what each feat does; there are a lot to choose from.

If your group is more familiar with 3.5 than with Pathfinder, remind them that you get a feat every 2 levels, not every 3 (so you should have 3 character-level feats at level 5).

Ok. So as your build already has a lot of set feats and such that you have to take we want to build upon that instead of trying anything new. So let’s take a look at feats and magic weapon enchants that effect critical hits or ways to free up any feats.

Not all of these options are possible for your exact build but I will add them for anyone in the future who wants to improve the build and has different stats than yourself.

Feats

It might be a little late as you have already taken it but the exotic weapon proficiency feat was not required unless you have a RP reason for the wakazashi. Kukri has the same crit range, they do deal less damage at a d4 though. The base weapon damage won't make up much of your damage in the long run though and it would allow you to dedicate your first feat to something more useful. You might ask your DM if he would allow you to use the downtime retraining rules located here.

Butterfly’s Sting

Prerequisite Combat Expertise, INT 13

Depending on your team you might also consider this feat as it allows your character to give up his crit to deal normal damage but the next ally to hit with a physical attack auto crits. So your big barbarian friend can deal massive amounts of damage if he has a low crit range weapon but a high crit modifier.

Surge of Success

Prerequisite: Human

Following the theme of using your high crit chance this feat gives you a +2 on a single attack roll, saving throw, skill check, or ability check of your choice before the end of your next turn if you crit or roll a 20 on a saving throw.

Equipment Enchantment

As you are after damage increase I will be focusing on magic weapon enchantments.

Magic Weapon page for reference.

Speed

Speed is a +3 enchant.

Speed is one of the more common enchants that players use. It grants an extra attack for each weapon it is on. So as your character dual wields that would be an additional 2 attacks at the character's highest BAB each round.

Element Burst

Again following the Crit theme the element burst enchants. Each is a +2 enchant

There are four of these types Flaming, Icy, Corrosive, and Shocking each of them auto adds 1d6 of their element to all of your attacks. And when you crit they deal an additional 1d10 damage. The cool thing about these enchants is they can stack! So you can have a Flaming Burst, Corrosive Burst weapon that deals normal damage +1d6 fire +1d6 acid on normal strikes and when you crit it becomes Normal crit damage +1d6 fire +1d6 acid +1d10 Fire +1d10 Acid.