Best way to become a VHL GM is to have a real passion for wanting to do it #1/2 below are things that get you on the list but #3 below you have to want it and fight for it when the time comes.
1) Do the basics of an active member point tasks, get a job, activity around the board.
2) Take over a VHLM GM position and see if it is something you really enjoy doing at even the minor league level.
3) If it is something you want to do have a real passion for it and don't be afraid to really get behind the cause. When I came back to the league around S27 trade deadline it wasn't long before Riga became an open position. I knew absolutely that I wanted nothing more than to become a GM again. Having just came back into the league though I thought there was no way they'd give me the position especially with how I ended my first GM tenure. I really let Knight know how much I wanted the job and the passion I had for being a VHL GM again.
4) Get lucky sometimes you just need the right set of circumstances.