I am not overly experienced with backpacking, but have done a variety of trips over the last several years and grew up doing lots of camping/other outdoor activities. One thing that might be helpful is to make a list of bare essentials--and bare essentials for normal living vs backpacking will be very different. You want light layers so you're comfortable as the weather shifts, and I would plan to re-wear the same clothes during your trip. I always keep my clothes in a stuff sack and then use that as my pillow.