+Enduvial
Thank you for notifying your level. I can try to help you as much as I can.
Using a pistol is not that difficult or complicated. It is a no-brainer to pair up your set with a shield, preferrably the Blackstar Shield available at the store. That shield, in my opinion, gives off the best (and crucial) stats.
For the pistol, I would prefer the pink Customized Hard 6. Again, it gives off the good stats.
I assume that you are a commando, otherwise if you're an operative or an engineer, I would highly suggest considering to use a different weapon that's much more suitable for your class. Anyways, the build you should use is this:
Neutron Stomp, Vigor, Singularity, Graviton Slam, Increase Mass, Kinetic Reservoir, Growing Rage, and Back Breaker. All maxed out, since you're a capped player.
This build is very commonly used by many people, and in my opinion, the best.
The tactics are not complicated as well, although practice can help. When you engage a fight, use both. Increase Mass and Growing Rage. This will increase your crit rate and your armor. Be careful with your Increase Mass though. It only lasts 5 seconds, so time it right. But no worries, just use it. It has a decent cool down time. I'l talk about more of this later.
So you engaged with both of the skills activated. when your opponent is within tange, use graviton slam to slow them down. This way, they won't move out of your range. Then, you must land a combo, as usual. You can use any of your knockdown skills you desire, either Neutron Stomp or Singularity. But I recommend using both of them at the same time. This will input more damage to your opponent, and just in case if the first skill gets dodged, your second skill will act as some sort of "backup". But I must inform you that you should use Singularity first. Singularity is a slow skill, and neutron stomp is a bit faster. In this order, the skills will perform at the same time, in range too. After the opponent is knocked down, use back breaker instantly after that. If it lands, you will land a combo, which deals more damage to the opponent. You will see the word "Combo" spring up from the player, which will notify you if you landed a combo.
I was talking about the Increase Mass earlier. It has a 10 second cooldown, which is decently fast. Use it very often, and check it often as well. Use it only when you're fighting.
Vigor is pretty self-explanatory. It boosts your HP regen, which allows you to heal fast. Try to use this when you are away from your opponents range. That way, you can heal more effectively. But when you must heal in combat, use Inc Mass and Vigor.
Kinetic Reservoir increases you MP regen, which restores your mana fast. It also boosts your damage at the last 2 seconds. It's good if you time the skill right and land those hits on those 2 seconds, but I don't really find it that effective because t's only 2 seconds. I mean really, pretty pathetic in my opinion.
And...repeat the steps. xD
What I do is use the wall a little bit for defense. That can be figured out easily.
And another note. Just because you're a commando and you have good armor, doesn't mean you can just go yolo on your opponent. Play defensive often, and strategically.
Let me tell you, a pistol + shield set is a good one for the commando. With the additional armor and the dodge with decent damage, it is certainly a good set to use.
Hoped this helped!