Here are a few tips that worked for me, and will hopefully help you navigate a revolving wardrobe.
Stretchier fabrics are best, and a-line shapes that hug the waist are the most flattering. Wrap, faux wrap, tie waist, or defined waist.
Similar to dresses, skirts can generally last for two (if not more) sizes. I'd buy one size down and wear it higher at my waist, and it would gradually get lower as I shed pounds.
3. Thrift/Consignment/Discount shopping
I don't thrift very much, but I did more so during the two years I lost the bulk of the weight. I'd thrift things like trousers and jeans that only looked great at one size. I'd also cruise Target sale racks, TJMaxx/Marshalls, and consignment shops for good deals on short and long term clothing. I got most of my jeans from the Gap using their now famous 40% off on Wednesdays coupons.
4. Shoes! Bags! Accessories!
I find that it is very important to have even a tiny wardrobe of items that fit well while your body is changing. Nothing was more frustrating than feeling proud of my progress, only to put on clothes and feel frumpy because they were ill fitting.
So how about you? How did you handle size changes when it came to your wardrobe? Any tips to share? Any questions?