Advice for my skill empower points

[Mobly]

Okay, don't laugh. I'm level 25 archer, and have not once used any skill empower points

I have 12 points, what do you recommend?
I have:

• Aimed Shot[2]
• Power shot[2]
• Poison Shot[2]
• Bone shot[1]
• Nature's protection[1]
• Multi-shot[1]

I'm on my way to see if I should/can level up any of these first.

Also, I mostly solo. I like skills that help me solo(I'm not against party, it's just my preference I guess).