Resources for joint miscuts

[destial]

So I've been working on my woodworking skills while I'm in the design phase on my first cabinet and have hit a few snags with miscut joints, have an woodworking class scheduled but it's still about a month out due to covid and small class sizes. Are there any good resources available for fixing up miscuts. I've found a few specific when I mess up a particular joint but haven't found any good general resources for things like when to use extension/insert moldings, or particularly how to fix mitre cuts if they're cut at to deep of an angle.

[destial]

For anybody else that hits the miter joint issue, I've found two things that seem to work for me based on a few days of reading/watching videos and then experimenting.

If it's goint to be painted using the sawdust and glue method seemed to work fine as you can't see the crease and the sanding allows it to take the color ok. If it's getting varnished then I've used a spline with just a bit of wood putty at the visible seam, that gets the varnished color close enough that you can't really see the crease unless you're looking for it. Supposedly you can do this with the sawdust and glue method but I haven't had any luck as of yet as the glue seems to leave it slighlty off colored (maybe I'm not using enough saw dust or the wrong type of wood glue). Depending on the piece of work and whether it's already assembled or not it might be easier just to recut it.

I haven't been able to find any good guidelines for when to use extensions (hopefully that's the proper term I've run across quite a few of them now), for when you mess up an internal joint like a mortise and tenon, so I've just come to the conclusion of see if you can extend it and keep it secure otherwise recut 

Please take that with a grain of salt as I'm still a utter and complete novice but that seems to be working for me so far, if there are better methods for either of those please fill me in. Next up is trying some pocket joinery, got my k4 in today

[jennifer]

I don't want to reccomend one of the most dangerous machines ever built, But a jointer can be incredibly accurate...Jenn only has a small 4 inch Rockwell, (rebuilt) but works really well for cleaning up long angled cuts.