Step 1 - Have your Date & Venue. This is far more important than you think it is, as your wedding date will effect delivery timeline, season and more. Your venue will also help you to envision yourself in the gowns and set the tone for your overall aesthetic/look
Step 2 - Figure out an approximate wedding budget. Of course, budgets always change… but you will want to at least have an idea of what you are comfortable spending on your dress, or if you do splurge, it will help you figure out where you will pull from/make sacrifices.