1) Let the small (and sometimes big) things go. Our pizza delivery didn't happen, but we had enough snacks and sweets for the kids that they didn't even notice or care.
2) Usually party places only give 1.5-2 hours max, so keep things minimal and delegate!
3) Costco/Sam's for drinks and snacks/food.
4) Also get decor that is returnable. My daughter changed her theme a few weeks before her party. I decided to give her the party she wanted and not guilt her into keeping it since I could return everything else.