It's very hard to actually comprehend any technically challenging concept without being constantly exposed to it. The more challenging it is, the more time you'

It's very hard to actually comprehend any technically challenging concept without being constantly exposed to it. The more challenging it is, the more time you're going to need so it become something like second nature to you. Take up as many relevant projects as needed to master the underlying theoretic aspects of whatever you're interested in, whether that's in math or programming. Don't get frustrated if you get stuck somewhere. You can always take a break and jump back to take a better look to any helpful readings to better understand some concept you may have missed earlier. Just make sure you're already pretty familiar with the very fundamentals first (e.g. don't expect good progress on a machine learning course without being already familiar with linear algebra - probability fundamentals.)