Perseverance is Key!
As much as it's hard to hear and accept, failure is a massive part of success. The process of trying, failing and then trying and failing again is exhausting and frustrating at times, but when you eventually get there, that win, no matter how minor, can be the sweetest.
Skills like double unders require perseverance..There's nothing more frustrating (or painful ) than trying to get them - but the day you get one, two, or link a few is always a big one.
Just ask David, who got his first DU last night after plenty of trying and failing, brilliant!