I'm not a great player, I have good and bad games, but some food for thought that are quick wins, some of it straight out of Basic Training!
1. Cover when reloading
2. Good use of flanking.... a minute without kills to flank the enemy can easily result in 4 or 5 good clean kills, using the outside on locker for example or the tree lines on the left and right flanks of Zavod
3. Awareness of surroundings and good comms in game (training is excellent to improve this)
4. Resist the need to move towards heavy contact, let them come to you sometimes!
5. Restrict movement at times like when capping flags. Movement attracts attention and makes you an easily identified target
6. Be aware of your arc of fire and the ingress/egress points of your enemy
7. Don't take the shot if your enemy hasn't seen you and you can't guarantee the kill, instead flank him and take his tags.
8. Use of med packs when digging in to a firing position, drop it (or someone in squad) so it's there before you need it, you can win loads of one on ones with it there that you wouldn't without.
9. Never contact the same enemy or group of enemy from exactly the same position twice if your seen the first time.
10. Wait for your enemy to reload, you can easily tell the type of weapon being used and you can use this to your advantage.
My K/D gets smashed on a lot of maps because I prefer the engineer class and spend a lot of time taking on armoured vehicles, other times my K/D gets smashed because I'm not really getting in to the game, however I always score high points by good use of whatever class I'm playing.