i respect you, you dont see many female gamers being open about it :D
anyways, try not to use the right joystick too much & for beginners it might help to turn the sensitivity to 1 or something manageable...
dont stop moving. constantly be on the move and try to anticipate the enemy's next move
this takes some practice but as you keep playing, you'll develop a good sense of what'll happen next
the energy sword takes some time to master because its an up-close-and-personal kill type of weapon.. so use the left joystick to strafe left and right constantly while simultaneously moving in on the target :D
dont forget to use your environment to your advantage (hiding behind trees can help for a short time, which can determine the outcome of a skirmish between you and your foe)
as for headshots, when possible, go for it! as mentioned, dont use the right stick too much - just slight taps here and there. keep the reticle high and head level
try not to spray and pray unless you need to (smoke or debris clouding your view)
uhh thats all i can come up with from the top of my head...
most importantly, keep playing and practicing and you'll get a lot better!
you can also go through the single player campaigns to get a feel for controls and weapons
good luck!