Editing is a very important part of Filmmaking. In fact I believe it is the most important step, because a good editor can make bad footage work and a bad editor can make good footage look horrible. So here's some tips to be the prior of the two.
Remove an Element
Watch your video without audio so you can focus on any visual or editing errors. Then watch it again with audio but without any visuals so you can listen for audio errors.
Use Compound Clips
Compound Clips can really make your timeline a lot simpler and make applying effects easy.
Shortcuts can help you move a lot faster when editing and most editors have a lot of them. Heres just a few from FCPX.
Think about the emotion and meaning behind each edit
Use J & L cuts
Cut to other person in conversations when they aren't talking to show reactions to other person
FCP X Audition
Drag clip onto one in the timeline and select add audition and then you can seamlessly switch between the two clips.
Information learned from http://www.lynda.com/Final-Cut-Pro-tutorials/Using-split-edits/111783/117365-4.html?autoplay=true
Zachary Will is an Award-Winning Filmmaker creating short films and content for the Internet as the owner of Riverside Studios. He has a Bachelor's in Film from Full Sail University. He has worked on productions for companies like Webmd, Sears, Home Depot, Six Flags and more!
"the trick is to never give up... I think the secret of success is not how little you get knocked down but how often you get back up." - Gareth Edwards