1) Top StickTop Stick is the brand name for the amazing double-stick tape sold at Sally Beauty Supply. If you're familiar with the product Hollywood Fashion Tape, Top Stick was there first. The clear 1" x 3" double-stick tapes were originally designed to hold a man's toupee in place. Wise stylists (or drag queens) discovered that the tape works miracles in keeping bra and slip straps in place, fussy collars straightened and gaps between buttons under control. It also works as an emergency hem keeper-upper. It won't harm even the most delicate fabrics or skin. The reason you should patronize your local Sally's, besides being a great store to explore, is Top Stick comes in a box of 50 strips for about $6.99, half the price of the other. Just remember to look for it in the "men's grooming" section.
2) Crochet HookA fine crochet hook can be used to pull snags in knitwear to the wrong side, where you can tie them off or weave them through— such a blessing.
3) Clear nail polishClear nail polish can hold loose threads on a button in place till you get a chance to re-sew it. Just be careful not to paint the button or the cloth. If your eyeglass screws keep coming loose, try a dab to "seal" them in place. And the classic use for clear nail polish? It will stop a hosiery run in its tracks— won't cover it, won't fix it, but will keep it from getting worse.
4) Full length mirror
You mean you don't have one yet?