Figure out an objective way to judge if a clip is good enough to use. Quality > Quantity
I usually gather clips that are okay for my standard, then make a notepad in which I describe the clips in short (kills, map, extra info like airshots/1v1s/not having heals/etc). Then you can rank them to find the ones you like most and filter out scraps.
Having a notepad like that also helps you orden clips in the video.
For example I make sure to mix scout, sniper and soldier clips equally so you don't watch 2 minutes of soldier frags, then 2 minutes of scout frags. Same goes for maps. This is just a thing I prefer though. Many people probably don't care about this.
You can keep scraps and use these for editing practise. It's up to you if you upload those as a scrap montage or just delete the project afterwards. These are just for learning things like transitions/smoothing/etc so your serious videos will turn out better. No need to spend hours on a scrap montage. Just throwing some clips together, figuring out transitions and maybe making a single smooth every now and then can help
Don't use minimal viewmodels in videos. A lot of people don't like the look of it. Regular viewmodels with viewmodel_fov between 70 and 90 are fine