Tight connections that can’t be helped? Reserve your seat near the front of the airplane. If those seats are already taken, check in at the counter and explain your situation.
Does your suitcase expand? If you’re shopping for a new bag to use as checked luggage, you may want to look at ones that expand.
Have you used packing folders? Similar in concept to packing cubes, these folders come with boards to help fold your clothes. How about space saving bags? These allow you to shrink bulky items like sweaters into smaller bags. Plus, they tend to keep out the wrinkles.
Pack things inside of other packed items. Shoes can hold socks or underwear.
Baby shampoo can be used as laundry detergent and to defog your scuba or ski goggles.
Dental floss can be used as thread or when you need some extra string.