1. Look for Basic Shapes- Everything in the world can be simplified into basic shapes. When you are studying your subject, try to pick out the basic shapes that make up the over all shape. Usually these shapes are pretty easy to draw. Draw the shapes then draw the contours (outlines). ( This tip will help you with your speed as well.)
2. Loosen Up- Drawing doesn't have to be stiff. For example, when you are trying to define the contour of an object, draw several light lines. You have a better chance of "finding" the right line when you draw several of them. Try holding the pencil differently than how you hold it when you write. Draw with your shoulder instead of your wrist by moving your whole arm when you make a mark.
3. Drawing is At Least 50% Observation- Drawing is about seeing. Have you ever taken a photo of something without pointing the camera at it? Of course you haven't. Yet so many people think they can draw well without looking at an object. Then they become disappointed that their drawings don't look representational. You must look at objects in order to draw them. In fact, you need to look at objects a lot in order to draw them. I suggest that the amount of time you should spend looking at your object should be half the time it takes to complete the drawing. Drawing is at least 50% observation. If you want to draw an elephant, then look at an elephant. Really study it. Understand why you see it that way, then draw it. When you draw, look at your object- the answers are there. Just put them on your paper.
4. Practice, Practice, Practice, and then Practice- This is the best tip that there is. You must practice. This is true of any skill. Keep a sketchbook and draw literally everything that you see. Draw everyday. When you can't draw, look at objects and imagine how you would draw them. What shapes are there? What values are there? Where is the light source? What medium would I use? Drawing can take place between your ears.