You can never have enough of these informative threads!
Another important consideration is confidence. Walking through a store with a sense of purpose and objective is important. Looking scared and nervous can draw attention you don't want. Basically look like you've been doing this all your life! Easier said than done, but possible. Took me a while to build up the confidence but after a while the scare-factor fades and it becomes more fun/normal.
A quick tip I'd like to add is comfort. For example, don't buy shoes that are a size too small just because they're the closest size to what you wish was on the rack. If you're comfortable in properly sized clothing, the self-conscious factor goes down and you can enjoy yourself more and focus on other things like posture, etc.
