If you are already having problems holding a stop, I would NOT recommend getting and trying to manage an SMB during your ascent. Although it does give you a point of reference, shooting a bag is significant task loading, and if your buoyancy control is shaky, adding that distraction will make it much worse.
I had horrible problems learning to hold a stop -- I was on my 50th dive before I managed it. I would recommend learning to ascend in a horizontal position, because you're more stable that way. Don't ever get too far off neutral -- inhale, wait to begin to rise, then exhale and see if you stop, and if you don't, VENT. Watch your gauge. If your gauge is on a console, pull it out and hold it in front of you. If it's on your wrist, it's easier. Pay very close attention to your ears and how your gear feels, to warn you when you are getting light. One thing Joe Talavera taught me is that there is a very small window where you can control your buoyancy with your breath; if you get farther from your desired depth than that, you have to use your BC or dry suit for control. So noticing variations from your desired depth quickly and correcting them early is key.
If you are vertical, any finning you do will drive you upwards, so if you choose to ascend in that position, remember that if you are going up too fast, you need to stop kicking.
Remember that your buddy is a visual reference as well. If you get a chance to dive with someone who has good buoyancy control and can hold his stops, that will help a lot.
Good luck with this -- It IS learnable. And people to whom it comes easily will not understand why you are having trouble, but I do.
I had horrible problems learning to hold a stop -- I was on my 50th dive before I managed it. I would recommend learning to ascend in a horizontal position, because you're more stable that way. Don't ever get too far off neutral -- inhale, wait to begin to rise, then exhale and see if you stop, and if you don't, VENT. Watch your gauge. If your gauge is on a console, pull it out and hold it in front of you. If it's on your wrist, it's easier. Pay very close attention to your ears and how your gear feels, to warn you when you are getting light. One thing Joe Talavera taught me is that there is a very small window where you can control your buoyancy with your breath; if you get farther from your desired depth than that, you have to use your BC or dry suit for control. So noticing variations from your desired depth quickly and correcting them early is key.
If you are vertical, any finning you do will drive you upwards, so if you choose to ascend in that position, remember that if you are going up too fast, you need to stop kicking.
Remember that your buddy is a visual reference as well. If you get a chance to dive with someone who has good buoyancy control and can hold his stops, that will help a lot.
Good luck with this -- It IS learnable. And people to whom it comes easily will not understand why you are having trouble, but I do.