http://forum.bioware...skyhold-builds/
At the start you get points in Long Shot and Stealth. Keep these, both are much needed! That gives us 2 points to play with. Goodie!
4 points - Level 5: First Blow --> Explosive Shot --> Pincushion --> Full Draw [Archery, Right side]
2 points - Level 7: Evasion --> Evade [Subterfuge, Left side]
3 points - Level 10: Caltrops --> Looked Like it Hurt --> Cheap Shot [Sabotage, right side]
2 points - level 12: Poisoned Weapons + Upgrade* [Sabotage, left side]
Best archer build. If you want to mix in some melee abilities, you can get Twin Fangs instead of Cheap Shot, and the 2 passives futher down to Deathblow instead of poisoned weapon. It won't be efficient.. but you don't got enough points to be efficient with dual setup.
However, if you want to be efficient, just get everything in the subterfuge tree and play more combo-oriented. That build isn't weapon-specific. I can't comment on it, as I have yet to try this build. (I'll get to that soon-ish!)