I understand you are very enthusiastic and I'll be kind to you - you want to learn which is great and you understand it takes time, which is even greater! You're changing too much, too often to really get an understanding for what the effect is. SLOW DOWN!!!!
First of all, strange as it may sound: put down the camera after you've take it of M-mode and don't touch it! Read the manual, it is an absolute essential thing that you don't go blundering into the menu changing stuff left and right without even understanding what you're doing. Really, I mean it in the nicest possible way.
Then take on one thing for a week, let's say focus modes. Set your camera to P-mode so there's one thing less to worry about
: the exposure. You've =been using M(anual) mode until now and it shows. P-mode will make a better selection of settings for now than you are capable of until you start understanding lens qualities and pitfalls.
Spend a week on the different focus modes, shooting a few different subjects and trying to get the camera to focus on different parts of the image. Use AF.S first with center point, then with different points you select and lastly with autopoint select. Then do all of that again in AF.C.
Have a look at the EXIF data in the image files to understand what the settings were, you'll see quick enough what worked and what didn't. Use an exif-viewer or your favorite image editor. Photome and Irfanview are both free downloads that offer an insight into the information hidden in the files.
Then, in a new week, explore the lightmeter settings, spot, area and center emphasized. Again, look at the exif to see what seemingly worked in which situation. You'll find that what worked on a landscape didn't necessarily worked on a portrait or closeup and vice-versa.
Work your way through the different programmed smartstuff in your camera but keep track of what you did and go about it methodically until you know your camera's most effective settings. Stick to those settings for a few months and turn to composition, subject matter, processing etc. before you move on.
I wish you good learning and please do not drive yourself crazy - we all went through this and there is a way out! GOOD LUCK!