I recommend reading
Mach Rider closely for hints and tips on what makes a moveset good. He has a perfect organisation - you can read each move closely, or skim it, and still get the basic info that you need (damage and knockback) out of it.
- He has a cool character and is not afraid to follow through with it.
- He presents an interesting playstyle which the character is clearly adept at; combining speed with moves he can do on the go to create amazing hitboxes. He also balances him out by giving him weaknesses like a poor jump speed and being a very large target.
- HE IS ON A MOTHERF*CKING MOTORBICYCLE. Add that something to make your character seem interesting and less generic. If he/she/it has a personality, then I want to see him/her/it kick everyone else's ***.
That said, you don't have to have everything planned out at the start; for the majority of my movesets, I let the ideas bloom in my mind for a few specials, then tried building some moves, playstyles and disadvantages around that. If you get the divine inspiration for the entire thing before you put finger to keyboard, then good for you. :D