Another tip: Do it when you're motivated, don't wait, because motivation might fade and not come back for a while.
We shy away from challenging, intimidating tasks on a psychological level by nature. Fighting through this is one of the few things that keeps us moving forward. If you're unmotivated to learn something but you really "should", I suggest you find a way to become motivated.
Consider a person who both wants to be a doctor, because they admire the direct nature of a doctors work, but they don't enjoy people themselves. And, also wants to be an engineer because they find it all more interesting and valuable, but they never particularly liked math. Depending on the person one choice will be more desirable and will be easier to learn motivation for.