I'm not a dress person either, although I do like skirts, in part because I rarely have to hem or alter them (I'm short-ish with short legs). I do think a good pair of "dressy" jeans can go a long way. Pair them with the top of your choice and a fun pair of shoes, and you're suitably dressed for all but dressiest of places or events. For those, I'd suggest a basic pair of black (or whatever color you like) dress pants. Again, pair them with a nice top and shoes and you're good to go.
Maybe I'm reading too much into your question and please forgive me if I am, but is there some other underlying issue that is making you feel uncomfortable in social situations? Body image issues, shyness, social anxiety? Maybe I've watched too many episodes of What Not to Wear, but it often seems that when people find it difficult to dress themselves, there is some other issue at the heart of it. The clothes are just representative or symptomatic of it.
I'll add this, too. While I used to like going "out on the town" with friends, I grew more and more uncomfortable in such settings the longer I was out of college. It's a "scene" that I don't care to be a part of. The women (and men) just seemed to be trying so hard to be hip and cool. While I'm not totally unhip, it all just strikes me as overly pretentious. I don't have the time or energy to care about it. My solution? I just don't go to places like that anymore. Thankfully, over time, most of my friends grew out of it, too, so it's not as much of an issue as it was 5-10 years ago. Now, we just go out to a casual dinner or brewpub. Or, better yet, we go for a ride or walk.
Good luck!
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher