Hoo boy, you're just at the beginning! Wait until she's a teenager, and the style is modern American slut -- that's when the real battles begin!
When my DD was about this age, she loved playing with dress up dolls and felt boards. I took my cue from her preschool teacher, and made a set of felt felt pictures with scenes of different types of weather and clothes. It's very easy to make felt board pieces. All you have to do is use pictures from a magazine or printed out from the internet, use fabric glue to attach them to felt, and then cut them out. No artistic skills are necessary! You should be able to find a felt board at an educational toy store. If not, just get a piece of foam core at a craft store and glue a large piece of felt onto it. You can get felt cut from the bolt at fabric stores, so that you don't have to piece squares together (this is also the most economical way to buy felt for making pieces, too).
I would play with my daughter and the board to teach her about weather and use a fan or heater to help simulate hot, warm, and cold temperatures. We'd then dress up her dolls or the felt board figures with clothes that were appropriate to the weather on the board, and then I'd ask her if she could find those types of clothes in the closet. I'd let her dress up in the clothes and then turn on the fan or heater, and ask her if she felt hot, cold, or just right. She very quickly learned that some clothes were better than others depending on the type of day it was. This was also a great way to develop logic and pattern-matching skills.
Once that connection was made, I would tell my daughter what the weather was supposed to be the night before, and have her dress the doll for that weather. Then I'd ask her to pick out 3 outfits that she thought she would like to wear the next day. We would look at the outfits together and I'd ask her to match the clothes she'd picked out to the type of clothes the doll was wearing. If the type of clothing didn't match, she would put it back in the closet and try again. After she had the right type of clothes laid out, I told her that she could pick any combination she wanted to wear the next day, and the other clothes got "the day off." This made getting dressed in the morning super easy. She had gotten to make all of the decisions, and the clothes were laid out and ready to wear. My DD is 17 now and still picks out her clothes the night before (as do I). It really speeds things up in the morning, which is always a rush time! In a way, she still plays with the felt board, because she loves designing her own clothing and is constantly pinning cloth onto her dress form to create new designs.
BTW, I found the felt board to be a terrific home educational tool for all sorts of things all the way through elementary school. My daughter also loved to use it for imaginative play.
My son was a totally different animal at this stage. He would only wear superhero costumes for about a year or so, and he would wear the same costume for weeks on end! I made sure to always have clothes available that we could toss on over the costume if he was too cold. We did run into the problem with him wanting to play and not get dressed on time for preschool at one point when he was 4. After 3 days of being late, I used a teaching clock to place the hands of the clock on the time we would be leaving, and told him that when the clock on his bedroom wall looked like the clock on his dresser, that was what time we were going, even if he was still in his PJ's, in his underwear, or naked! He tested this theory just once, and I ended up tucking him kicking and screaming in his underwear into his car seat (but at least he was the ONLY one who was screaming!). By the time we got to school, he was crying. I had brought a set of clothes with me and gave him the option of finishing dressing in the car, which he did. The next day, he was dressed within minutes of getting out of bed!