Welcome to the hunting family! Use your head and be safe. If you question the shot, don't take it.
You did not say if your 30/30 is a lever, pump or bolt action, but I will assume it is a lever action. If you have the funds, I would buy a .22LR rifle in the same action as your deer rifle and use the same set-up. You will eventually save the cost of the .22LR in ammo savings. For safety reasons and ethics, you also need to become proficient with your firearm, and this will take a lot of regular practice.
If your 30/30 has a 2x7 or 1x4 scope, do the same with the .22LR. The scope on the .22LR does not need to be as good of a scope or the same brand on your 30/30, but have the same recticle. An example is if you have a Circle X (Bushnell) or Pro Diamond (Simmons), have the same recticle on your .22LR. If you have the normal cross-hairs, put the same on your .22LR. If you have iron sights, do the same with the .22LR.
Practice with your .22LR a lot to become very safe, accurate, proficient and comfortable. Do your practicing in real world surroundings. If you will be shooting from a stand, practice shooting from a stand while wearing a safety harness, properly fitted and attached to the tree. If you will be shooting from a ground blind, practice shooting from a ground blind having the proper backstop. I always use a shooters sling, so my bolt action .22LR's also have a shooters sling. Once a firearm is sighted-in, I am not a fan of bench shooting.
See if there is a firearms instructor in your area who is willing to work with you. Most would be glad to do this at no fee. If money is not a problem for you, offer to pay the instructor as money may be a problem for them. Maybe you can do an exchange of services.
Check with your doctor regarding starting an exercise program. Begin slow and steadily progress. Start to do exercises to improve your ability to steadily hold the rifle on target. Practice holding on target with your unloaded 30/30 rifle while wearing your upper body gear (jacket, etc.). Once you can do this well with a normal heartbeat, trying doing it with an elevated heartbeat. Run in place, do push-ups, sit-ups, weights, etc. to raise your heartbeat and then work on holding your unloaded firearm on target as steadily as possible. Always treat every firearm as if it were loaded and know whether it is loaded. If you set it down, check it when you pick it back up.
Once you become accurate with a .22LR at a distance of 50 yards or more, shoot at least 10 rounds per month of the 30/30 while continuing to practice with the .22LR to become proficient with the 30/30. Get some snap caps for your 30/30 and practice dry firing in real world surrounds, keeping your sights on the target before, during and after pulling the trigger with a snap cap in the chamber. Do not have any ammunition in the area while dry firing.
Do not climb a stand with a loaded firearm. Do not raise or lower a loaded firearm to or from a stand. Practice getting into and out of your stand while wearing your hunting boots and hunting clothing.