Here’s what I do if it helps. Whatever you do don’t have a long continuous shot from your helmet cam! Try to mix it up with short varied clips from different view points, close ups, general scene, etc.
I usually copy an existing "template" project which has about two minutes of 2 second clips and my standard title and ending. The clips all have a very subtle zoom in which is the only effect I ever use other than colour correction. In preview I set the start of clips and drag them onto the existing ones and generally keep the template clip length.
After viewing the project and adjusting any clip scenes for position etc I will take time to fix the audio. Often I triple tap to separate the audio and will stretch it to adjoining clips. I also often copy simple scene audio to clips which have a good picture but accidentally include extraneous noises. Wind noise I'll eliminate whenever possible and when the scene is obviously windy I add a wind sound effect which sounds like real wind rather than microphone wind noise. Fade transitions are sometimes useful between audio clips.
Music I only use when the project doesn't have much real world audio. I drag the music onto two audio tracks, one matching the start and the other matching the end. I then trim the overlap and adjust until the transition sounds natural. It's all trial and error but I do like music that starts and ends properly rather than just fading in or out. All the time I'm erring on the side of making the project shorter rather than longer. Deleting unnecessary clips is useful when matching music length.
Colour correction I usually leave to the end so I don't waste time fixing clips that I later reject to fix the project length. I try to avoid jarring changes in light from one scene to another using the levels slider mostly and sometimes gamma to lift the shadows. I will also adjust saturation to hopefully normal levels which aren't too exaggerated by the camera used.
Exporting
I don't generally publish so you won't find any YouTube advice here. Before exporting I've named the project with key words preceded by the event date in YYYMMDD format. This is to make files sort properly with the actual event date rather than the file creation date.
I export to Photos and then copy that to Files/OnMyDevice so I have a version which doesn't have to download first. I tag these into categories and also create a link to the file which I add to a map app because often the fastest way to find a video is on a map.
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Some of the footage I keep unedited for my own use - review for later - ie. Dirt bike riding - listening to the engine sounds, watching how I am riding the trails. This type of footage doesnt need much editing at all. I'll piece a couple of shots together and render that with a basic title. 
