I've heard there are certain habits that worsen the degree of myopia (nearsightedness). what are these habits and what i do do decrease the degree?

There may be some: There have been some studies showing that children who use night lights, perform excessive near tasks, and spend few hours outside, have an increased chance of becoming myopic. That being said, it does not necessarily lead to nearsightedness.

Myopia: Nothing can stop ther progression of myopia. There have been rigid gas perm contact used for this, orthokeratology, but is very self limited. No amount of reading c an cause the myopia to progress. Best to have your vision checked annually and get the myopic correction to keep you seeing 20/20.