How to take good pictures from my nikon D5200?

How to take good pictures from my nikon D5200?

Same as how to do anything else well. Work at it. Study. Practice. Learn from your mistakes. Don't assume that a couple of years with a camera makes you a photographer. Be curious. Experiment. Fail (and, as Beckett says, fail again, fail better).

You are like almost everybody on this web site that buys into the situation that if you don't have a DSLR, you can't take good pictures. That is false. It is going to be harder for you since you like many others have started with the "roof" of learning rather than the foundation (a nice bridge camera).
So my advise before you go out and waste money on lenses that you don't known wether you need or not, is to start with Scot Kelby books. I especially like this author as he has a web site which he gives you "real" world excess to for 60 days after your book purchase. They are easy reading and speak in your language, (photographically speaking).

Start by reading the owners manual.
You can get a lot of photography tips on youtube.

Learn the basics of photography, read your camera's manual and spend a couple of years practising what you have learned.

There are thousands of photography tips which can be recommended.far too many to list them all here.
Search YouTube
Buy/Borrow photography books
Get some tutorial DVDs
Above all, PRACTICE! Take hundreds of shots and see what works and what doesn't. Take the same scene with different settings and see how it changes the image.

Go to YouTube and learn the basics of your camera and photography and videography