+1 for both what Matt and Mark said
I've worked on quite a few low-budget shorts in the past few years, so situations where I have to run outside with a Zoom and a crappy shotgun mic to record ghetto foley pop up waaaaay more than I'd like them to.
As far as how I work, it is much easier for me to record and chop up my un-synced foley so that it corresponds to specific sonic elements in a given action rather than trying to sync an entire recording by making awkward edits all over the place.
Take this example; if you're recording or cutting foley for someone smoking a cigarette, you'd actually have something like 5 elements to record and place:
- mouth closing on cigarette
- cigarette sizzling
- lips smacking as cigarette is withdrawn from the mouth
These would be placed separately and crossfaded into each other (if it's even necessary).
So, for skating, I'd assume it would go something like this:
- pushoff from stop
- skate coming back down and contacting the ground
- pushoff while moving
- skate down
- brake and stop
So, record some push-offs from a stop, some skating at different speeds, some steady coasting (down a hill?), some turning, and then some stopping, some skate downs, etc. This will probably take a long while, but by the end of it you should be able to chop it up and cut it back together into something convincing. Also, recording too much material is definitely better than not recording enough, so don't get lazy!
One more thing: MAKE SURE you record plenty of tone at the location where you're recording the skating. Good tone that matches up with whatever is going on behind your recordings is crucial for hiding edits. This is especially true if you're outside.
Good luck, and hit me up if you need any clarification.