Usually when my overseas friends come to visit Thailand, we would usually take them to one of the Central Plaza outlets. At the Central Departmental stores, the ladies would usually be able to find clothes, handbags or shoes that they like.
A tip I have is to shop during the sale time. During their sales period, the discounts are deep with many items up to 50% discount. You can refer to their English website https://www.central.co.th/en/ to check if there is a sale going on. If you visit Central during year end, there are usually massive sales and discounts available.
My friends tend to shop here because there is a larger variety of clothings and they can take their time to browse and try on the clothings. And there is enough variety so that for those who do not like shopping (like the guys), there are other places in Central such as bookstore and gadgets store that they can consider visiting.
Central have some very nice ladies wear for both casual, office or function wear.
Above are more casual wear, Indie style from the brand Journal.
There are also elegant evening dresses and formal wear. There are also beautiful high heels or stiletto which is good enough to be worn by a bride.
Not forgetting the underwear, especially the Wacoal bras where the pricing here is much less expensive compared to in other countries.
Aside from that you can find hair accessories, costume jewelry, necklace, handbags and shoes being sold in the ladies section.
One of my friend from Malaysia who walked a lot (as she does not drive and take public transport) would always be on the lookout for comfortable shoes that can be worn to work. She told me she was able to get some really comfortable shoes that are reasonably priced from Central.
I am also similar, as I tend to want to be able to shop at a large shopping area and to be able to try on clothes or items without being followed around by sales person.