So I want to play the game with champions I like, but too often I keep on making mistakes that drain my will to continue playong whenever they happen. I want help so that I don't ake those mistakes as much anymore.
I play these champions mid
I want to get better, and please don't say that my picks are not viable or something like that.
Sol needs the most Positioning out of those three champs so overall he is the hardest of the three since you have to put your self in danger to do the most.
Veigar is an unlimited stacking champ so look to freeze the wave and clear minons with q more than anything since it's your safest way to stack your ap other than hitting other champs with abitiles. Note that your w is one of the easiest to dodge skill shots in the game so only use it for quick wave clear (when shoving for a back) or if you land your e otherwise the other laner will dodge it (unless they are blind as hell lol). Your ult is best used to finish someone off as long as you have about 200 ap (easy for Veigar to get) and they are at about 10 to 20% health you can kill them with it which is free stacks. Also note that you get the most stacks off of cannons so you want to make sure you are always clearing those with q more than any other minons. While Veigar is a close(ish) range burst mage you need to stay back in lanning phase because you are weakest then since you have no mobility and only one disengage (your e) which has a long CD. TLDR: stay back farm with q kill cannons with q only w if they are stunned or you are shoving for a quick back.
Viktor: unfortunately I dont have much for this champ other than mid to late game is where you shine (more so mid game) you can have insane burst plus a move speed boost in your empowered q which can be great. Your w is best used as a zoning/ disengage tool as opposed to an engage tool.
This will probably get removed. I made a post here recently along the same lines and it got booted for being on the wrong board. I wouldn't know where the right one is, they don't say. Just... Be ready for that.
Before it is, my response: It's tough to say for sure without knowing which specific mistakes you make, which in turn would be hard to measure without watching several of your games. Thus, I'll give you general advice in case you don't already do it.
On casters, positioning is key. Realize that most of the time when you cast, you're making yourself vulnerable for a brief moment, and your enemy can take advantage of that. Try to catch them while they're lining up a minion, casting themselves, something like that. Something where an animation will delay their response. Also make sure you're positioned in such a way that allies can support you when necessary.
Try to stay behind your allies, but not so far behind you're exposed. Always keep some allies close enough that you can run to the other side of them if an assassin jumps on you.
Manage your cooldowns efficiently. Only use combos when you're pretty sure you can get the kill. Otherwise, save successive abilities for emergencies. If your opponent knows your champion and sees all your abilities are on cooldown, they'll jump in and you'll be helpless. Try to save full combos for securing kills or teamfighting, and always create distance after you've popped off an ability or are waiting for a cooldown.
Don't be afraid to give up early farm if you're up against a scary opponent. If you're up against a M7 Yasuo, it's probably a good idea to miss out on some farm rather than let him jump on you and Q you to smithereens.
If your stuns don't take immediately, withdraw! Even in teamfights, create a little distance and get closer to your tank. In lane, definitely retreat towards tower. Like with 3, assume the opponent knows your champion and can recognize when your CC is down. He'll probably try to capitalize.
Hope these help a bit.
well you can already recognise your own mistakes. write them down, assess why they happened (watch a replay if you must), and correct them. you would have no hopes of improving if you couldn't recognise your own mistakes so that's a pretty good start.
I'm not going to lie, those three champions don't have great carry potential for the average Joe.
Of the three however, I would say you have the best chance with Viktor.
If you want to learn to carry from the mid lane, you need to learn to be a good roamer. Search videos on how to roam and apply lane pressure.
as someone who went semi pro in another game (Counter strike) and had tryouts for pro teams I can give you the steps on how to improve.
Really Important steps 5. Practice with a purpose - dont say just win the game, start with like having really good CS, then add another objective of to ward more after you can do that consistently you add something like focus on not dieing more than 3 times a game, etc.) Eventually the first step of CS well will be natural, so will warding. This is why you can add tasks to your list over time as building blocks of the basics you need to do without thinking. I think my list had like 45-50 items on it by the end. With like the first 30 being basics of every game then the last 20 being more advanced things. 6. Analyze your games - Biggest thing for improving is analyzing each game you play and take notes on things you did well and things to improve on, Did you hit your objectives in step#5?
Mechanics will come with time as you play more and more
Slowly expand your champion pool 1 at a time. You cant learn 6 characters at once to the level you need to.
Once you get to High plat/Low diamond (plat 2- Diamond 3) take a lesson not for 1 game but multiple games so they can see what you do over a little time.
Don't give up and Practice practice practice. It took me about 10k hours to get to good then another 5k to get to semipro level.
You can learn a great deal about map awareness playing 
A mechanic that's helpful for all champions but is very strong for
i dont play mid at all so i dont know if there is any way i can help you other than other aspects of the game. Such as warding, trading, minion waves, jungle tracking, macro and what not. if you interested, let me know.
I don't play mages so I can't help much. Outside of game though, spellcheck would do you wonders.
