Posted this guide to reddit the other day, and I'd like to share it with you guys in the official forums. There will be follow-ups to this, so keep an eye out if you're interested in learning more! Thanks for reading.
This guide is based largely on personal opinions. This is not new information, nor do I claim to be a professional player. Take all suggestions in guides with a grain of salt.
Hi! I'm xemnaught, and I fell in love with League of Legends a few months ago. Since then, I've gone through an enormous learning experience. There's a lot to League of Legends, and part of why I like it is because there's so much to learn without sacrificing accessibility. Anyone can pick up this game and learn a lot about competitive gaming. I would just like to share with r/LoL some exercises that helped me learn to play AD effectively by practicing them frequently.
II. The AD Carry Role
There are no easy roles in the current meta-game. Period. No matter what role you pick, you are faced with an endless path of learning and improvement. There will be few highs and a LOT of lows. The AD Carry is largely considered to have the most game-changing potential role in the meta.
There's no such thing as a useless role either, so every player on the team will have an influence on the outcome of each match. The AD Carry seems to have a big impact because of the late game (45:00+). After such a long game, victory is nearly always determined by the outcome of a big team fight. At this point, the AD Carry (if played correctly) will be doing the most damage in the fight.
III: The Goal
Do you ever find yourself reluctant to get into queue by yourself? Even I still lack a bit of confidence when queuing alone. It's very normal to be intimidated since the community is so unforgiving. The objective to this guide is to help you expand your comfort zone, slowly and surely. Practicing your skills will even help you play top or mid lane!
IV: Tips for Before You Queue
Everyone knows you get gold from last-hitting minions, much more than you ever get from champion kills/assists. There's a simple exercise you can do to improve your creep scores. Create a custom game on Summoner's Rift and play alone without bots. Select the AD carry of your choice and practice those last hits worry-free of enemy ganks or harassment. If the lane pushes, simply move to another. Don't purchase any items except your want to start with.
There are two main reasons you should do exercises like this first thing when you log. It warms you up, and consistent practice is the best kind of practice. Make a pattern! Practice as soon as you log on, after you take a break, etc. Developing these habits are essential.
Stepping it Up
You can add a bit of challenge by adding one or more bots. Be sure to add one with a ranged auto attack to simulate laning with another AD. Practice harassing without losing minions. Go for kills when you think you need practice securing kills. This isn't as reliable since the bots available in custom games are only Beginner and aren't very intelligent, but it's better than no opponent.
Add a Benchmark
Determine the number of CS you wish to reach by 15:00 or 20:00. Log your result and go in again. Set records for yourself and constantly try to beat them. This is something you can do in ANY game to improve skill. I would suggest starting by trying to get 100 cs by 15:00. You can adjust it from there as you improve.
Play some other AD carries to get a feel for their attack animation, mana costs, etc. If I buy a new AD, I immediately take them into a custom game with 1 bot to practice their moves. You want to have a varied set of tools to choose from if your preferred character gets taken or banned.
Watch the Pros
I don't mean for builds (AD carry builds can be pretty static anyway.) Watching your favorite team's AD carry play can teach you a few things. Watch how they position themselves when farming. Pay attention to how good positioning can get you gold while avoiding harassment at the same time. Watch how they position in team fights as well.
Learn to use Shift+Right Click or A -> Click. This helps when kiting or when "Stepping" your auto-attacks to stay as mobile as possible while saving you time by not requiring you to move your mouse to click on a champion. This allows you some safety when kiting by making it impossible to accidentally click and move out of position when trying to kite.
V: In-game: Above and Beyond
The ability to press buttons quickly with good aim doesn't make a good player. There's a lot of mind-gaming in this game's community. Reign of Gaming has an interesting article describing how you can increase your ELO just by refusing to press the enter key. Only chat to relay important information that can't be relayed through ping.
If you're in a good mood, say nice things to your fellow players. If you see someone make a good play that ends up killing you, give them some credit instead of getting mad that you died. You'll begin to be able to focus more clearly when completely separated from the drama and rage that runs rampant in many matches.
VI: Apply What You've Learned
Everything you practice while playing AD carry can be applied to any other lane-farming position. The team fight experience you get as AD carry carries over to any role. Don't neglect playing the other roles, or you're game will be stagnant if you're forced out of the AD carry position. Practice farming/harassing with top-laners instead a few times. Practice everything mentioned previously.
The biggest mistake you can make is deciding you have no more to learn. You'll ALWAYS have more room for improvement. If you're really serious about your game, I hope you'll take some of these tips into consideration. I may add more in the future. If you're interesting in playing with me, add me in game (NA) and I'd be more than happy to play matches with you.