@halo572I may add that its important to find loadout and playstyle that suits you. I personally went through multiple specialists, even getting T1 for them, before finding the one I like. The same goes for guns.
And with the BF2042 loadout system, your gun can change ALOT with the attachments you unlock.
Don't start with difficult guns. AM40 is definitely a beast, buts it's a more "advanced" weapon. It has high ROF and quite a substantial recoil that kicks all over the place.
If you want a great starter weapon, try M5A3. Unlock short barrel at 120, BCG light grip unlocks at something like 10 or 20 kills, extended mag at 2xx kills, but 30 round mag is still great for learning and picking off single targets. Once you have 40 round mag unlocked, along with short barrel and BCG grip you have a beast that defeats 95% of the weapons out to 70m distance.
As with the general gameplay, take it slow. Don't run in guns blazing and screaming. That's what most of my kills are in this game. People who think they can rush others.
Slow down, stop looking for kills, and start looking for cover. 2042 are poorly designed, so your best option is to move from cover to cover. This allows you to bring your fight to the enemy, rather than getting fight thrown at you out of nowhere.
Learn spawn. One of the most important aspects of approaching any flag. If you begin capture enemy flag, you must know where enemies will spawn at you. It instantly gives you a huge advantage to lay low and wait for them to come into your sights.
EDIT: One of the best advice I've ever got from a high tier player was to lower my sensitivity. Going down to 1% ingame and 1200dpi on mouse made my k/d go higher and higher with each game. Onbisouly don't drop it down to 1% if you're running on something like 25% and 3k dpi. Do it slowly, and you will start getting results.