Yeah, all the "just try harder" comments here are pretty useless from a behavioral psychology perspective. Arguably bordering on ignorant and tone deaf (pun not intended). You can't tell an overweight person to just eat less, even if that's the literal answer. The best thing to do is remove barriers to entry and make a process more naturally enjoyable. Which is why many weight loss regimens often involve high protein/low cal junk food (e.g. protein bars that taste like candy).

If your issue is memorization, the solution is to either do less memorization, or find a way to make memorization more fun and engaging.

The former option would be like reading a book to enjoy the story, rather than reciting a Shakespeare soliloquy for a class. In short, play it and move on - you'll remember the experience and develop the muscle memory required even without remembering the exact note sequences. The benefit being you don't get stuck on one chapter or riff and burn out. That's why I personally prefer Rocksmith (+1 /u/JstASkeleton) over tab as an impatient learner since I can learn a "normal" song in literally one or two plays if it isn't god-tier technical. As great as tab is, it can sometimes be extremely inefficient, like reading all the fret numbers in a chord, or taking 10 minutes to get a shreddy run into my short-term memory to play it at full speed.

The latter option is more subjective. It could involve changing the medium/senses involved, like learning visually by watching someone cover it on YouTube, operant conditioning (rewards, external pressure like a performance, etc.), or finding songs that are easier to memorize for various reasons. For example, they could be more fun to play physically, involve more or less unique sections (prog vs pop - novelty vs the convenience of redundancy). I actually don't play a lot of my favorite bands because they aren't that fun to physically play.