Rough workflow for me is:
1. Get all the clips you think you're going to work with in a rough timeline for the project, as well as the b-roll/artsy shots. They're generally separate and in an 80/20 or 70/30 ratio. All of the skating clips followed by all of the b-roll on one timeline so you have a "bird's-eye" view of what you are working with.
2. You watch all of it a couple of times and aggressively pare down sub-par footage, weak angles, "slow" footage, sketchy stuff, etc that on further reflection doesn't work. You can always put stuff back in if you really think you need to, but the further you get into an edit the less inclined you'll be to take stuff out.
3. You start moving stuff around into an order that makes sense (into montages, sections, parts, etc) and start highlighting certain tricks by slow moing clips, putting in roll-up/ride away shots, second angles, etc. Putting in "openers" and "enders" on the sections.
While you're doing steps 1 through 3 you should be periodically throwing on random songs and watching to get a feel for what direction you want to go in musically. A willingness to experiment goes a long way here I think. Different genres, time periods, moods, etc. When I'm editing, I'll also listen to music on youtube at night to try and discover new songs or sounds that I think would go with what I'm making.
4. This is where the music comes in. I generally let time requirements/constraints in each "section" dictate the music and not the other way around.
Example: I'm making a 3 and a half minute throwaway montage, so I'll look for songs that are around 3 and a half minutes in length and see what I can use that meets that parameter.
Helps "box you in" to narrow song choices down. But if you are married to a song choice that doesn't work for the time limits of what you're trying to do, you can always fade a song in/out. I try to avoid it though.
5. Then comes the tedious work of editing everything to the beat, nailing transitions, moving things around, trimming or slightly expanding things, adding/removing clips or angles. Edit, edit, edit. Watch it all the way through several times and makes sure there are no errors or mis-timed moments/awkward or slow-feeling moments. Get a second set of eyes on it. Gather limited feedback from people you trust. Use that feedback.
6. Repeat step 5.
Curious to hear how other people approach the editing process! I'm sure there are many pathways to success.