This is mostly about portait drawing...
The truth is that, at the begining, none of us were great at these things at all. I've only got a question, after you took the pecil in your hand, could you ever let it down? Here, on deviantART, there are so many people that have evolved so much at drawing. In the past, if I tried to draw after a picture, there would be a lot of mistakes, but, in time... some mistakes disapeared and I can't wait untill the day when no obvious mistake will seek place in my drawings and I hope the same for you. Now... I want to share with you a few steps you have to take to get better, let's hope I'll follow them too:
1. I heared of a lot of great artists that became so good after, at first, they begun with anime drawing.
Now, this step is not only about anime. You can begin with cartoon, anime or other types of nice drawings. Don't worry if your first drawing doesn't look good right from the begining... It takes time, a lot of drawing and a lot of cartoons to watch, studying their looks. Use reference pictures to help you.
2. Don't forget about tutorials. They hepled a lot of people very much. Why wouldn't they help you, too? Just search for them. There are a bunch of good ones here, too.
3. Start trying to create OC, original characters. They will help you draw without having a reference picture to guide after. By the way, if you ever create your own cartoon or anime, you will need to create your own characters so this step is very important if you want to follow that kind of career.
4. Slowly try to turn your cartoon/anime drawing style into real drawing, if you want. You don't need to take that step if you fall in love with anime/cartoon drawing. Even so, once in a while, trying another style is fun.
5. Perfect your drawing. Try to keep the mistakes from coming to your drawings. Even though they seem not to want to leave, if you keep practising, they will get bored and soon leave.

Those are all the steps I have for you. Now, I want to share some great traditional drawings I love.