Recently a friend of mine told me he didn't want to work on a project because he had such high standards he didn't think he could accomplish what he envisioned. So many of us designers can relate to that feeling but not starting at all would be our biggest mistake. Same goes for young designers who are just starting out. You have to start somewhere. Don't put off making your portfolio or a project because you don't feel like you have the skill set. Start somewhere. Start today. Then iterate and reiterate. Will your project be better after the seventh iteration, most likely but you can't get to the seventh without the first. Don't let fear hold you back from expressing yourself creatively. Will you fuck it up? Yes. Failure is the only way forward.