I’m in the process of switching up my shopping style, too. I’ve had a few too many last-minute, grab-whatever-looks-like-it-might-fit shopping trips the night (or morning!) before a special event!
Lately I’ve been trying to hit up a few select stores once every month or two. I love Filene’s Basement and almost always find something there at a phenomenal price (their clearance is incredible!), so that’s my number one store I try to visit regularly. I also like DSW for shoes and New York and Company for work clothes (they frequently send out “take $30 off of a purchase of $75” coupons, and when you’re shopping the sale rack, that makes for some pretty good deals!).
I also try to go to as many stores as I can during semi-annual and seasonal clearance sales. In January, after the holidays, I did more shopping for myself than I did for Christmas gifts! But everything was on sale, so I felt justified.
I try to do “preparation shopping” - if I see something I know I’m likely to wear in the next year or so, and it’s on sale, I’ll buy it. I know I have a bunch of weddings to go to this year (and next), for example, so when I see appropriate dresses on sale (I’m talking really on sale - usually under $15 each), I buy them. I know this method could come back to bite me in the butt if I over-buy, but so far it’s been working very well.
Hope this helps!!