First get Maya Purple Card.
Horong card -> sight for close range, detect for long range, if it's long enough DS, if they're too close (grimtooth, soul breaker, auto-hit) charge arrow.
Traps do wonders, just hard to play with in PvP.
Auto-shoot sucks in most cases, they use poison react (ED armor works well then), so against assassins it's better to Double Strafe.
Valkyrie Manteau doesn't give reflect, that's only for swordsman, merchant and thief classes and guess what, you're an archer class -> no reflect from Valkyrie Manteau.
High Orc card is so useful that you have to switch to shield everytime they get close to hit you and you need to switch back to bow to charge arrow and keep switching items like that.... forget that, you're a sniper you rely on bow, switching takes too much time, live with that fact.
Metalling card and Wikebine Tres card for stripping their weapon and armor (if they don't use Full Chemical Protection) always comes in handy.
Last thing, range is your friend, their Soul Breaker, Grimtooth or whatever ranged skill they got is way much crappier than your sniper range, abuse that fact.
If you want a good fight go to potion PvP so the noobs don't ygg 24/7 to reach you.