for one helmet cams on rails dont look good so switch up your angles.
cut out the time in between hits or waiting for you friend to get a 3rd person angle of him.
try to keep the camera steady if you are going to do the walking around the car thing in the beginning (which i wouldnt recommend without a stabilizer its just not worth it)
synchronize the music to whats going on in the film (ie. take offs/ taps with beat drops ect.)
longer edits are more boring unless you are doing ridiculous tricks so maybe 2 minutes max for your level
slow motion is good in moderation
watch tons of edits really. get ideas of camera angles, what looks good as a viewer, and stuff like that.
maybe invest in some equipment or build some yourself (ie. i made a mini steadycam rig for my gopro)
3rd person shots are usually better just mix it up it wasnt half bad for a beginner editor.
hope this helped
snowboarder but good stuff
a good example of a good edit
kinda long but entertaining as i said before ridiculous stuff
"skiing without poles is like getting a handjob from a dude. it feels good until you look down and realize that you're gay."
"Stylin' and Profilin'"