Before you jump into deep learning, I would strongly advise you to do a few introductory machine learning courses to get up to speed with fundamental concepts like clustering, regression, evaluation metrics, etc.

Here is a thread including a few recent courses you can explore:

"Create machine learning models"

by Microsoft

Note: the module on clustering is really good!

https://docs.microsoft.com/en-gb/learn/paths/create-machine-learn-models/

"Stanford CS229: Machine Learning"

by Stanford and Andrew Ng

Note: One of my favorite ML courses of all time!

https://www.youtube.com/playlist?list=PLoROMvodv4rMiGQp3WXShtMGgzqpfVfbU

"Machine Learning Crash Course"

by Google

Note: I took this course right when it was released and I was immediately hooked by the focus and high quality of it.

https://developers.google.com/machine-learning/crash-course/ml-intro

"Introduction to Machine Learning for Coders"

by Jeremy Howard

Note: I have seen a few videos from the http://fast.ai  courses and I can easily understand why their courses are so popular. Very hands-on approach!

https://course18.fast.ai/ml.html 

"Foundations of Machine Learning" by Bloomberg ML EDU

https://bloomberg.github.io/foml/#homeworkslave

Note: If you love math and theory, you will like the depthness of this course.

"Tabular Data"

by Machine Learning University

Note: This course touches on important machine learning topics at a high-level using easy to grasp explanations and examples of machine learning applications.

https://www.youtube.com/playlist?list=PL8P_Z6C4GcuVQZCYf_ZnMoIWLLKGx9Mi2

"Stat 451: Intro to Machine Learning (Fall 2020)"

by @rasbt

Note: Sebastian keeps adding awesome machine learning content to his YouTube channel and I really appreciate the content he puts together. Very approachable!

https://www.youtube.com/playlist?list=PLTKMiZHVd_2KyGirGEvKlniaWeLOHhUF3

There are many other courses out there but I can only talk about the ones I have taken. Feel free to share if you have found other good ones out there. It would be nice to share your experience with the course and why you like it or found it useful.

Additional tips:
- Make a list of topics you found interesting & challenging
- Do more investigation on challenging topics
- Practise coding
- Share code
- Write notes
- Write/report on some interesting new result/idea you got
- Take your time
- Engage in ML forums/discussions