This achievement is all about perseverance. There isn't much of a guide to write for this achievement. That said I have a few tips for those trying to expedite the process.

Don't do the guitarcade unless you have a mission to do so, these are some of the easiest and best missions as they help teach you.

Session mode missions are sometimes the worst (play 1 hour straight) to do this the easiest way is to cause feedback to trick the game into thinking you are playing. when you have actually just gone to lunch or something.

After guitarcade and Session missions have all been done missions are pure RNG based and randomize every time you go back to the login screen. Take advantage of this to get easier missions (50 note streak) over harder missions (get XXXXX score in YYYYY song)

Most of the get __ note streak can be done at the beginning of a song and then quitting out as soon as the streak is gotten. This is a bland boring way of achieving this, but it is the fastest.

Each instrument gets 3 separate missions every time you log in. So to speed things up check each instrument before randomizing the missions again

Keep a counter of how many missions you've done to help give you some sense of where you are at.

Don't force this achievement, play a song or two you like and then do some missions. If you don't you will more than likely grow sick of this game.