I second most of the tips above. I've just survived my first year of baby so these are what made me feel more myself:
1) Get a great haircut - preferably now while you can so you don't have to worry later when it is harder to get the time to yourself.
2) If you are nursing - nursing tanks are your friend. Buy a bunch because inevitably they get spit up on, you leak through etc and there is enough laundry as it is LOL.
3) It is a drag wearing any maternity clothes but some crossover to post-partum is inevitable. After I'd got over the first month I tried to spruce myself up with a few new accessories, a fab pair of (low heel) MOTG shoes (although be aware that if you are still carrying a lot of fluid, your shoe size may shrink back a bit as time goes on - it happened for me so don't go shoe crazy), a new fun necklace or scarf, and so forth.
4) If you do buy tops or dresses early post-partum and you are nursing - remember to get something that is stretchy enough or opens (wrap tops, dresses, stretchy v-neck, something you can lift up etc.
5) A cute baby bag you really love can help - since you use this a LOT!
6) If it is winter, leggings and other stretchy layering pieces are your friends.
7) Don't go crazy buying clothes because your shape may change a lot in the first couple of months. Everyone is different but it might be better to let your shape settle down a touch before you get too many items.
8) Be kind to yourself. It is a massive ask and very tiring and sometimes it will be hard enough to get time for a shower. If you look unwashed and frumpy some days it is temporary - and it does get easier.
9) All the very best!!!