Persistence is a skill that needs to be trained just like all skills, intellectually gifted people tend to get little training in it because they learn stuff fast and thus don't get the usual amount of training in it like others, so what you need to do is pick a thing you want to do that's boring and then measure the time of how long you manage to do it in one day, then you reward yourself with something, next time you try to do it for longer than last time and if you manage that then you give yourself another reward. It's just a skill, it's hard to train but train it you must if you want to be good at it. There is nothing more to it sadly, its a simple problem with a boring simple solution, you just have to put in the hours and train that skill.