First, have fun with the game. If you've ever played something offline with friends, you'll probaby notice it's easier to watch yourself lose or not understand something but still recognize that you're having fun anyways because it's you and your friends having a good time. You're just less focused on the competitive/dominance aspect that normally drives online play. Enjoying the game is like the number one fuel to keep going no matter how obnoxious something actually becomes, and if it ever stops being fun, think about taking a break until it's fun again or changing the circumstances to make it fun again. Switching characters, formats, playing friends offline instead of online, playing drunk, whatever works to make it something you really want to do.
Second, when something's giving you a problem that you feel you need to improve to beat, think about the game as objectively and detached as possible. When you get mad, all you can be is mad and it doesn't help you get to the root of the problem. When you stay calm, determined, and focused on solving a puzzle, you at least set yourself up for succeeding eventually, even if it's not as fast as you might like.
Third, be patient and confident. You really need to believe that those two things I mentioned above will work. Having gone through those processes repeatedly so that you have experience with these methods/ideas helps a lot, but when you're starting out just having a lot of patience and confidence is kind of a blind step. Do it enough, and it'll be like second nature. You'll feel better about your successes, feel more confident in tackling your failures, and most importantly, enjoy the experiences the game throws at you. Mostly. <3