The best tips I can offer are these.

1: Never use your Dash or roll to initiate a fight, you ALWAYS want these for escapes as mobility is your GREATEST ASSET.

2: Salvo and Exploding arrows are your friend. For all range classes in DF AOE's are your best friends.

3: If you are having trouble with aiming (IE: you are not landing shots with at least 75% accuracy I highly suggest playing some quakelive with railguns only. I say this because pvp in DF does not really give you the chance to get many reps in unless you are dueling/training a lot. If it is hard to get practice in the game itself then my opinion is that since quakelive is in a browser it is easy to get shooting reps in while you do your harvesting or whatnot in the actual game.

4: Learn when to shoot and when to not shoot. Make your opponent burn their cool downs and learn your distance for when to switch to your 2 hander to offer a quick burst when your enemy closes the gap.

5: CHUG CHUG CHUG and EAT EAT EAT. Anytime you are engaging or even think you are about to engage get your food buff rolling and the SPLIT SECOND you take damage get your pots rolling.

Remember, DF is a shooter so you have to have your shooter skills up to par.

Hope that helps at least a little.

[Linked Image from nodiatis.com]