Unfortunately I don't the opportunity to exercise a lot of what I have learnt about this due to money restraints but this is a bit of what I have picked up (mainly through competition clay shooting but it applies just as well to any form of shooting) First of all, forget the phrase 'practice makes perfect'
Any parctice method that is worth doing should start with the only slightly, but importantly different, 'perfect practice makes perfect'
I would forget what gun you take out, the aim must be to get to the desired level with each gun you have. (Not always possible for a good many reasons but that is the starting point.) If you can't practice to the required level with all your guns use just one for as much as possible. We all love to use different guns but get to know one as best you can. I have a very 'one gun - one cartridge' mentality.
I will admit here that I have guns coming out of ears but out of four shotguns in my safe you will find my trusty old Beretta in my hand 95% of the time and it probably fires 99.9% of the shots. I trust it, know how it works an have 100% confidence in it. Rifle wise I only have a 22LR and .243 so they have their very specific purposes.
First thing to do, is set up your practice session so you know what you're doing. No point blindly firing expensive ammunition for no gain.
Fortunately with a rifle there are a good few less variables than with moving targets. I would set up a tin can or similar and at 10 yards standing, pop it. back to 20 yds, pop it, 50 yds, pop it. etc etc. do this standing, free hand until you miss. when you miss try again until you hit it. back 10 yards do it again. Eventually, over time you will find you are getting further an further away without realising it. Do this for each shooting position as appropriate. If you are in your comfort zone say shooting prone you start at 50 yds, get to 60 yds but at 70 yds you miss when you would normally expect a gauranteed hit out to 90, stop, back to 50 and start again. You can set up appropriate tests for each rifle, with your stalkig rifle maybe sart at 25 yds free hand, 50 yds off sticks and 100 yds prone as your starting skill and shooting position dictates. Once you have shot a full series say prone shooting at a target with stalking rifle at 75, 100, 125, 150, 175 & 200 and have a succession of one shot hits, Stop you can do that. Move on. Anyone can lay on a range at 50 yds punching holes in a paper target all day and it will get you exactly nowhere.
My old uni coach would have me shoot a clay target where I wanted. Now shoot it 5 yards quicker, 5 yards quicker, 5 yards quicker, miss. back to the beginning and quicker, quicker, quicker until he decided it was too quick. then back to the middle. Slower, slower, slower until it was well out of range. right you can hit that, back five yards! we even used to work a grid system, that was hard work!
Practice what you can't do, make it hard for yourself, shooting off sticks at 100 yards, 150 yards etc. You will find that your technique will improve slowly and allow to consistently shoot at ranges and from positions that you didn't think possible.I'm not gettig into a debate over the rights and wrongs of shooting off sticks at 150 yards as its to each individual to decide where their level of competence is not sufficient to ensure a humane kill.
Finally, If you can't do something ask someone who knows to help and enjoy your practice. Its not a chore!
I am far from an expert in stalking and matters of training but I have learnt how to practice my shooting and it works for me. Unfortunately as I say certainly my shotgunning is starting to slip through lack of practice now but my rifle shooting as I am doing a bit more is improving no end.
This has turned into a bit of an article but I hope it is something to think on and it might even help a bit!