Depends on what you are designing. Perhaps you are designing some business cards. You need to know a few things before you begin, this way they don't become problems. Will it be one color or multiple, will it have foil or embossing? The answers to these questions determine the process of your design. Following the proper file preparation guidelines would ensure you don't have any problems. Let us know if you have any business card designing questions. Cheers!
I usually feel that my designs are inadequate after designing something if it happens to look too complex or too simple. This usually leads to me getting caught up in it trying to perfect it until I'm pleased with it, which can take some time. It usually takes up too much of my time which is a problem because I have other things to work on.