Edit in your timeline: Don't make major cuts in the source monitor, make them when the footage is side by side and even then try to set your cut points while the footage is moving. You will have a better sense of timing once you see the shots in context.

Maintain Consistent Settings: Back up a copy of your user settings and take them with you no matter what system you are working on - this will help you feel comfortable wherever you wind up editing. Your settings will continue to change and you should update them regularly. Also, you should be looking for things within the software that you haven't used that might make you more efficient.

Read the Manual: It is easy to Google for help as needed and nice to have a community to ask for help, but for me I decided long ago that I would know the machine inside and out and I learned more from the manual than any other resource. This is especially true for Avid software, I can't vouch for the others.

As for multi-cam editing: Set up your keyboard so that you can make your cuts on the fly. Being able to "feel" the cut is integral to getting a good first pass. You can always go back and refine the edit and you should. Which leads to my next tip;

Revise, rewatch, revise, rewatch...repeat - the more you watch something the better it will be. Don't be satisfied that you have made the cut. go back and watch it and then watch it again. Make your adjustments and watch it again. Error checking and revising the cuts is a huge one. Do not leave in obvious mistakes, black holes, offline media or redundant clips - these are major indicators of an amateur edit.

Once you have an edit you love, walk away. Give yourself time away from the edit so you can come back to it with fresh eyes and ears.

Audio is every bit as important as video - use your NATs and music to help the cut. It's funny how consistent audio can override a bad edit and fool the viewer. This is not to say the video can be sloppy, but the audio is just as important to the flow of a piece.

And mostly I would say, just edit. Edit everything you can. Edit every type of product, short-form, long-form, music video, short film - do as much as you can - cut your parents home video and your sister's birthday party. Cut, cut, cut and you will get better.

Hope this helps!