How can I make her feel as good as possible?

I told my boyfriend the same thing for awhile. He'd start through my pants, but end up going through my panties. He never really paid any attention to my clit or anything, just kinda put his fingers in me through my panties. It felt good, but unless you have some kind of toy handy, make sure to pay attention to her clit. You're not gonna get anywhere without it.

Ask her what she likes.

Touch her.. see how far you can get your fingers without jamming her panties too far. breathe into her ear and whisper things you know will turn her on.

Get a toy, you'll have her cumming through her panties in no time flat.

Listen to her voice and do what brings more excitement and breathing.

Simply by massaging her through them. Also, you could kiss her while you are doing that.

Use the back of the head of a vibrating tooth brush...if you don't have a vibrator on hand....that should make her cum pretty hard....if not then spice it up a lil bit...use your imagination.

Believe it or not you can still do plenty that way. A lot of women only benefit from clitoral stimulation. Some women can experience overstimulation as well. This may be to your advantage. The most important thing is to make her comfortable, I have been there. It turned out she was just shy about totally getting undressed, do not let it be a problem. Like it was said above "listen to her breathing" she will let you know whar's right. Just keep your pressure, rythme and speed constant once you get there. Too many people change when they know they are hitting the spot.