There are a few ways to approach it, depending on your subject matter and what kind of techniques you'd like to practice. Drawing exactly as you see will help your observational skills and help you understand the Z-axis (foreshortening, depth perception) in addition to pushing your draftsmanship, while stylizing can help foster your caricature skills and add "life" to your drawings. I feel that it's important to work on both, as they're both pretty important techniques to understand, especially for illustration and the like.
If you're still new to the whole "realism" thing, I'd recommend starting off with monochrome. Color is incredibly intimidating on the first go. Focus on the lights and darks of what you're drawing, and then slowly start working up toward color. How I learned it was: monochrome (blacks and whites) -> sepia tone (blacks, whites and brown) -> limited palette (blacks, browns, some yellow and blue) -> toned down palette (no black, brown and red/blue/yellow) -> full range palette (red, blue, yellow).
If you're doing a still life, it's best to try to draw strictly what you see, using careful measurements using the tip of your pencil, your thumb and a straightened arm to figure out exactly where things are placed and the distance objects are apart from each other.
http://drawsketch.about.com/cs/figuredrawing/a/fig_proportion_2.htm]Read this for more information. Figure drawing can also be approached in the exactly as you see-method, and for the most part, it's important to draw as realistically as possible at least once in a while. If you choose to stylize the figure, it's important to stylize
what you see as opposed to stylizing someone beyond recognition. Caricature the person.
The best reason I can think of why I'd prefer to stylize instead of draw-exactly-as-you-see is for gesture drawing, short poses in an academic setting
or drawing out in public, such as in the mall or something. In a classroom/workshop setting, you'd typically have only 15 seconds to 3 minutes to draw a pose. The point of gesture drawing exercises is to loosen up your drawings while still making it look readable. Because you'll have such a limited amount of time, you will need to exaggerate the figure.
Here's some of my 3 minute figure work. I had to push the figure out more to heighten her pose, and push her facial expressions to match. This is definitely something you can get your friends/family to do. I'm sure they can hold a pose for 1-3 minutes.
Out in public, you'll also have to stylize/caricature your drawings since nobody is going to stand still for you (unless you make it really obvious). Observe people and try to draw what they're doing, as opposed to who they
are. For example, a boy chasing after some pigeons versus just a boy.
I apologize for the information dump, but I hope you find it useful. Learning to draw from life is probably the best step any artist can take into rapidly improving their skills. Good luck!
