Drawing Tips for newbies and experts, based on my experience:
(1) Do not force prospects. When in a drawing some detail can't be appreciated, leave it aside. It is better that it is "incomplete" than a misshapen thing.
(2) Take care to proportions, which is essential and as important as caring prospects.
(3) Caring for the location of the drawing in the sheet, either to make our drawing fit properly in it or to make it look better.
(4) Always remember the vanishing points. It is very important to be guided by them if you do not have a trained eye. They go together to the perspective of the composition, and can ruin all the work if you use them wrong.
(5) Work on the details, because in these is the strong point of each work, what differentiates it from the others.
(6) When drawing people or characters, work on expressions. We can draw an EXCELLENT picture, but if the face is expressing otherwise, the drawing is useless.
(7) Understand what you draw. Always try to copy as closely as possible what you see, and try to understand how is composed that figure. I mean, if you are drawing a vase, look at: which basic geometric shapes are used to achieved that figure, how light affects it, what types of shadows are generated depending on the angle of the light, see how point of view affects the perspertive, etcetera.
(8) Try new things. Always experiment with new techniques, based on what you see in other artists, what do you like, what you find easier or comfortable to you, and so on. You can always change your drawing style, you can always add more details or change ways of coloring, sketching, shading.
(9) The secret of perfect technique is practice. You should try to do at least 10 sketches a day, of whatever: people, houses, animals, food, I don't know.
(10) You should take care of all the tips, but mostly 7 and 9. With those two you already understand the others. With persistence and observation, you learn and you record it oon your head. With this knowledge, you can invent or create tyour own pieces of art.
(11) and ULTRA IMPORTANT: Finally, take your pencil and paper and go to draw! :3
Thanks for reading.
(and sorry for my bad english, I prefer spanish XD)