Everyone has their own method of drawing and colouring, but here, I'd like to share a few tips that I have grown accoustomed to using that you might like to distort and use for your own work!

Drawing branches off into yet another two sections. Drawing from reference, and drawing freehand.
Drawing from reference is more mathematical, while freendhand drawing requires vision.

A) From Reference
When drawing from a reference, the I find that the best way to keep perspective and proportion is by looking at individual lines and their relationship to other lines. Look at the reference logically and concentrate on little details.
i) Think of the image as the first quadrant in the Cartesian Plane.
ii) When a line curves or changes, find out where that line curves or changes by comparing that changing point to another line in the picture that changes at about the same "x" or "y" coordinate.
iii) Look at the approximate angle measurements betweent two lines. While drawing from a 2 dimentional reference, you might even want to take out a hand-dandy protractor to aid with line relations.
iv) Sometimes people have a tendancy to believe that their picture should be congruent to that of the reference, this is not true. Yes, the proportion should be as similar as possible, but that is still not that same thing as congruent. If you're aiming for congruency, you might as well trace the image ...
v) Again, search for relations between the lines. For line lengths, the ratio between two particular lines on your drawing and the equivalent on the reference should be the same.

Drawing Freehand
The problem with freehand drawing is that it rarely comes out exactly how you invisioned it to be. Freehand drawing requires you to have a strong vision of what the finished product would be. You look at the big picture when you freehand. I don't have many tips for freehanding because I pretty much such at it.
i) To aid with a clearer vision, start with guidelines and sketches of the basic form of the image. It is a lot easier to find out that you made a proportion mistake when you see everything there in it's place.
ii) Remember not to change the angle of your "vision" final product half way through. For example, if you're drawing a human hand (ew, why would you do that anyway?) you should hide the fingers that can't be seen from the angle your drawing is at (duh) ... but seriously, you don't know how many creatures, myself included, change the angle of perspective for one or two things just because it's easier to draw ... but the whole thing ends up screwy as a result. EXAMPLE (bad perspective on the shoe).

Ahhh, colouring, one of my favourite things!
Colouring starts with great, easy to blend, and vibrant colours ... Prismacolor!
i) To begin with, DON'T colour in one direction. While keeping the coloured pencil on the paper through out the process, change the direction. To make the colouring even, keep the pressure on the page constant and add light layers over areas that are not even. Sometimes, when you have a blunt pencil crayon, colouring in tiny circles makes the colouring very smooth while not having it too blendy if that's the texture you're looking for.
ii) Don't you hate colouring when there are white spots between the colouring? Well, for smooth colours, start with a base coat of the colour beige. Add the colour of choice and keep blending it with the beige or white pencil crayon until you have the right consistency. EXAMPLE
iii) For shading and transitioning colours, add the transition colour where you want it, while releasing pressure as you move away from that point, then use beige or white to smoothen out the colours. EXAMPLE (see the shirt).
iv) Also, while generally you shouldn't colour in one direction, it is a good idea to colour in the direction of the object you're trying to depict. It adds depth. EXAMPLE (see the armor).
v) While blending is nice, it is important not to over do it or your whole image will be too blendy and messy. EXAMPLE (see that the line between the sand and the water is messy). Don't keep blending in white and beige after the consistency is acheived!