3. Try going to the store onely one time
Before getting your list of supplies (and any additional materials you want to buy for your creative work), you need to make sure you've put everything down on paper. Hopefully, going to the store a few times won't create a significant problem - it might take longer than you think.
Imagine it this way: you are 30 minutes away from the store, so each time you go, driving takes at most limited hour. Plus, the time you have to seek for items and ask for help. This redundancy can quickly turn a quick ride into a two or three-hour challenge. If you do it two or three times more than your schedule, it can make you feel like you're struggling or falling behind. Do whatever you can to prepare them before you go shopping, so you know what you need.