It just takes practice. That is probably my biggest tip. Practice, practice, practice. That's the only way to get good at it. Learn the hotkeys for whatever program you are using, they make things go by way faster. Spend as much time as you need editing your videos to get them perfect, ctrl+z is your friend to undo things and redo them over and over and over again. Also, don't spend money on an expensive editing program until you know you are comfortable with editing. The free ones, like Lightworks and Hitfilm Express (I just switched from Lightworks to Hitfilm, Hitfilm is definitely they way to go), can be just as powerful as the programs you pay for.