My main advice

1. Start easy.

It's tempting to grab a textbook or video series because it gets good reviews on Amazon or likes on YouTube. That's all good and fine, but it's more important to get a good introduction to the topic. The key here is to get a rhythm going and it's very easy to disrupt your study rhythm if you start too hard. So, much like working out, start out easy, with something you can easily grasp. Moreover, do less than you can. As they say in weightlifting, leave a couple of reps in the tank. Don't go all out as you're running a marathon, not a sprint.

2. Be consistent

The key to finishing something is to do be consistent. Intense 5-day seminars can work, but you're going to need a very good teacher and have a lot of motivation to get through it. For self-study, consistency is much more important. I would recommend somewhere between 4-10 hours a week. Anything more than that is going to burn you out and anything less and you'll forget previous lessons. 1 hour a day for me on a given subject and taking weekends off works for me. The key is to build up momentum and keep it going.

3. Power through by stepping back.

There will be sections where you're going to feel lost. You're going to feel frustrated or not know what the text or video is talking about. This is where you need to "deload" a bit. Take a week to review all the material you've learned so far and redo some of the exercises. Everyone has these and the key is to not lose momentum. Many a study has stopped due to one obstacle. The key is to step back for a bit and try again without losing the momentum you've built.

4. Remove distractions.

Not everyone has the discipline to follow these, and most of the time your brain will try very hard to distract you when you encounter a hard problem. The key is to minimize all your distractions during your study time. This means no email, social media, walks to the fridge or anything else. You start and don't stop until you've finished your hour (or 30 minutes or whatever you committed to). It's okay if you only got through 2 pages during that time as long as you didn't get distracted. Give yourself permission to stall a bit. And if this happens a few times in a row, step back and try again (see 3)

5. Get a buddy

The best way to study is with someone or some group that's studying the same thing. There are lots of forums for all of those topics that you can engage in to answer some of your questions and possibly find someone to study with. Getting some accountability is an excellent way to keep up your momentum.