My actual first time with a girl (I was on top), was more like a dare. I mean, she was a butch and most of them don't like to be touched all over or anywhere for that matter. Now this girl was allowing me touch her and since I was given the permission (more like, she wasn't really stopping me) I just went ahead and touched everything I wanted to touch. To be honest, I felt so... weirded out by all of it. Like, I was concentrating so much on what it actually felt like to be aroused by the whole thing. I was enjoying myself nonetheless. She enjoyed it because she 'finished'.
What was the question again? What I would do differently?
1. Not do it in daytime or at least in a very illuminated area. It makes you more conscious about your body and it might kill the mood.
2. For the first time, take it as slow as you need to. If you're the one inexperienced and the one you're with isn't, it's safe to bet that she would be sensitive about that. She would know to do it in your pace and not hers. If you're both inexperienced, then go to no. 5.
3. Remember that if you're already in that situation, and she's not saying stop, don't. Go for the gold at the end of that rainbow!
4. I wish my first time was more intimate. This one, I'm not sure how to explain very well but, like a hug and a kiss, it will flow naturally.
5. Communication is key. Don't be afraid to ask if you want something done (i.e. to the left, a little bit to the right.. lol). You get the idea. Also, pay attention to her reaction to your touch. It tells you if she likes it or not. You can also guide her head, her hands and pretty much her whole body to where you want her.
I hope somehow that made sense.