Check out a great book by game designer Wlad Marhulets.
Getting started with game design? The topic is too complex to master without some help so here's something that might help you make the first steps. This ebook by Wlad Marhulets features 100 tips and tricks on the basics like points of interest, how to design jumps and more. Do you know the best part? The book is free!
"Some of these lessons were learned by making countless mistakes, others from GDC talks, youtube videos, fellow developers, and articles," wrote Marhulets. "I did my best to link to sources if I managed to find them or remember them. Some tips are genre-specific. Others contradict one another. It’s up to you to use them or not. Ultimately, breaking rules is the prerequisite to innovation."