I need some guidance how to develop myself in deep learning
I am not an expert in the field, but I'd like to share with you my personal opinion. Taking online courses and reading books is great, but the problem is you don't get to practice much on your own. I know there might be assignments and projects included, but they're mostly guided and pretty straightforward, or related to a certain topic of the chapter/lecture. 

However, real world problems are a bit different. They usually encompass several smaller sub-problems that might not be clear at the beginning, and there are a plenty of choices that you have to make on your own. Usually you'd have to try several solutions before you're confident what suits your problem best. I believe it's something you learn mostly by practice. So I think given that you have enough knowledge now, it's about time to use your knowledge and build interesting stuff, stuff that would speak for you. Kaggle is also a great way to move forward, since there are tons of competitions and data sets that could inspire you, and help you know where you stand among others. With every project you try to do, you discover something new or learn to appreciate something you already know more. Plus you can always learn from others who publish their kernels. 

Whatever you choose to do, I wish you all the best :)