I'm in the same boat as you, good sir.
I've been getting owned for the past week, but here are some things I've learned:
1. Think of what you would do in COD--- do not do that.
2. Flank instead of confronting the enemy--- chances are you'll get killed if you run at them.
3. Recon is not just for sniping--- blow as many buildings the enemy can use up, and most importantly, spot as many enemies as possible.
4. If you notice that your respawns are getting further and further from the target, get to the target and allow time for some people to get to you because that sniper at the other side of the map is not the best place to spawn.
5. Get used to the flow of the game--- COD had really smooth, flowing controls, this feels like a real war simulator/W@W gridlike controls.
6. Don't get into a hellicopter/atv/whatever vehicle and just leave it in the middle of nowhere because you haven't learned how to use it yet--- leave it where people can find it.
7. Burst fire--- all the time.
8. Wear a headset--- this drastically improved my game experience because the people I'm playing with seem like they're new as well. Most of the time, if you have a mic people will actually take some advice or follow your requests (didn't say orders) because they're also either lost in the game, or simply tired of getting killed from trying to rush an area.
9. Use all of your kit before you die--- it's counterproductive if you couldn't even take down a wall, resupply someone, heal someone, spot someone, or repair a vehicle before you die. Get something done before you die!
10. Keep moving--- if you kill someone, the only think they'll remember is where you were when it happened.
Oh... and stop playing TDM... this game wasn't meant to be enjoyed through death matches. Rush and conquest are the reasons this game was made. You'll notice the two game modes are much more enjoyable than TDM.
If you're sticking with TDM because that was the norm in COD (which I did) you'll get bored easily. Especially since you have the full map and it moves incredibly slow from the getgo.
Well that's about all I can write before I start playing again. Please keep in mind the information above could be 100% to veterans. And to veterans: please correct if any of the above seems off.
Good luck