How to sort out the understanding of theme development for wordpress?

Question

themeforest

something I understand myself but could you continue this list?

1. footer and header markup
   
2. menu layout and styling
   
3. styling tags by input type
   

Answer 1

Take it and do it! Everything will come with experience. The main thing is not to carry a complete copy-paste from topic to topic. Try different things. Look into the themes of other developers.

Answer 2

Everything that you wrote has little to do with Wordpress specifically. You have now described the usual work with HTML.
Look at Youtube wordpress courses from Webdesign Master.