First off, its easy for me to agree the best way to learn a game is to learn from someone else who already knows. The best learning experience I have ever had was my first game of Merchant of Venus. And the big benefit for it was we had a seasoned Merchant of Venus veteran who knew the ins and outs.
And I'm not talking about someone who played it once before. This guy owned the original 80's version, had the tokens separated into little bags for each player, and had the relevant places for most of the normal roadblocks dogeared in the Avalon Hill rulebook for easy reference.
Very rarely does this happen with games in my own collection. If I'm playing a game someone else owns, chances are I'm going to avoid getting it since I already have access to it.
What happens instead is I get a sealed box, fresh new rules, a bunch of counters to punch out and no idea what I'm doing.
My ideal procedure:
1) Read the rules beforehand. The rulebooks of today are amazing creatures for the most part. Inside you will find clearly laid out turn sequences, spelled-out special abilities and even examples with pictures. I enjoy reading rulebooks with the best of 'em, and reading the rulebook WELL in advance of the actual play session takes quite a bit of the stress off.
2) Mock play-throughs. Around the World in 80 Days - I played a solitaire game of this before I ever showed it to another person. The rules for this game are really simple, with a quick turnaround between players to keep the game moving. After I completed the solitaire game, I tried out a 2 player game with my wife. She is usually pretty good about finding instances where I am wrong, so this helped me iron out spots I understood but had difficultly explaining to others.
3) Play the first real live game with completely willing participants. Pick friends who have played many games with you before. Ideally these are people who love playing games and want to play games of their own volition. DON'T buy a game you think your in-laws are going to like, and then spend time trying to show them how to play when you are somewhat unsure yourself. To the non-gamer crowd, a person with a huge 6 or 8 page rulebook open in front of them is a dangerous warning sign of eminent boredom. You will be avoided and/or escaped from and the earliest possible opportunity! The same applies to kids, who normally are happy to try any crap you try to lay out on the table but who also quickly run out of interest if the game doesn't start moving at a brisk pace.
The Internet-connected world of today provides a wealth of information. Watch It Played and the How to Play podcast (and I'm sure many similar smaller operations) offer up huge amounts of information as to how the rules of a game are actually supposed to fit together. You can also sometimes find free-to-play online versions of board games which can really help with parts 2 and 3 of the procedure.
a game lobby, full of willing participants!
Neither Youtube or places like yucata figure into my rules learning process because in all likelihood I will have already used all these resources WELL BEFORE I ever purchase the game! Not only do I learn the game, but I can actually figure out if I want to spend my money on it in the first place. It's like giving your wallet a time machine…90's me would have never imagined such as resource as he was busy blind-buying gems like Lunch Money from the local Shinder's (now under new management!).
Don't skip any steps just because you've seen the video or played the game online. It is a seductive thought that you might be able to be an expert without muddling through the rules in the real world, but the great thing about video games is also an incredible hinderance to proper learning. All the little rules questions and bookkeeping are taking care of for you, automatically, and you are going to have to figure this stuff out…sink or swim style…before you play that first live game!
Learning the rules in all the wrong ways:
The absolutely last thing I want to do is have someone else read the rules out loud before the game begins, and then try to absorb the information using my amazing mutant powers of procedural memory recall. It doesn't work that way!
Instead, my eyes glaze over and I am unable to process a single thing he is saying. It could be a foreign language, or just gibberish. Whatever part of the human brain in charge of processing oral instructions, it is forever broken to me.
After the verbal assault, this method invariably switches to "figuring it out along the way." If I have a question, I'll ask. If I don't know what an action exactly does, I'll do it and see what happens. The first game you play shouldn't be competitive, and I never play it as such.
If I don't grasp the strategy of the game right away, the second and third game might not be very competitive, either. But usually I will figure it out. And hey, I'm playing board games so the day is looking pretty rosy already.
The absolutely worst rules learning experience was entirely my fault. It was my first play through of Pret-a-Porter, which it turns out is actually a really fun yet demanding economic game. It will be my first experience with this game that forever pushes me to do better in learning my games. Because its not just me I hurt, but the poor souls who had the optimism to attempt to play a game with me.