I stink at timed play myself. But from what I have learned/experienced... some ideas..
1) know your openings and endgames. Not saying to memorize 47 opening variations, but know some solid lines and enough theory to not waste time in the first few moves. If you do not know the openings you will either waste time or fall into a trap or mess up, losing right away (delayed perhaps but still lost in the long run). Endgames as well, if you get there and are low on time, confidence that you know what to do and execution of a win is much easier.
2) play on their time as best you can. Keep THEIR clock running, not yours.
3) practice and play a lot at slower controls, and gradually speed up. Trying to go fast right off is just going to lead to tons of mistakes.
4) You are going to miss stuff. Accept it and roll on, do not get bogged down on a single move. Find a solid move as best you can and make it, if you missed something better, well your opponent has the same time problems you do unless they are a blitz master or something.
5) Don't worry about it. Fast games are garbage. If you don't believe me watch the 2k+ rated guys going at it in the "watch it live" section here. You will spot all kinds of blunders in those games if you go over them afterwards, or if you are very low rated, let a computer show you how bad some of the moves are.
I am just getting back into chess and I find that I am able to see the board fairly well and am able to play decent moves when I play Online games but when I play a Live game with time pressure, I feel too rushed and I always end up making a terrible move early and I blow my position. I guess I just need to play more Live Chess and work through it but if you have any tips/experience on improving in this area, it would be much appreciated. Thanks and it's great to be on Chess.com!