BiggusGeekus said:
My anatomy teacher in art college said something that I totally agree with. He said, "Some people talk about needing to be born with a 'talent' for art. Talent will only get you about 10% of the way there. The other 90% is just plain hard work and study."
True, some take to drawing faster than others. But nothing beats straight up hard work. Repeated drawings and lots and lots of pencil mileage is what makes your skill go up.
A couple of other factors that'll help you learn are: a personal desire for it and an open mind (meaning , be humble, listen to those that come before you, also keep a clear head and be objective with your own art). Desire helps because it is what gets you to sit and draw for hours and hours.
I personally recommend seeking out a good art teacher at the local art college. You might find one at the local adult community school or whatever, but ....usually, that's a coin toss on whether you'll get someone good or not. Ask at the local art college what classes are for the freshmen. What classes are the fundamentals. Should be like, structural drawing (perspective and shapes), anatomy, color design (learning how color and light works), 2-D design (how to compose art), etc.
The only thing is, these classes cost money to take. But hey, if you're really serious about doing it, then its worth the investment. What city do you live in? Most major cities have a fairly good art college.
And once you get in, take your time. Absorb all the knowledge the teachers give ya. Practice and master the basics before moving on. This is very important. Its like taking martial arts too. You can't do the cool higher level stuff until you master basic stances and punches. Don't be eager to skip ahead.
Also don't be discourage on how long it'll take to get to the level you want to be. Just keep at it. Let's for example pretent it'll take you 8 years to get decent. Long time eh? Well, if you think its too long and quit, then the amount of years it'll take before you can draw will be "never". Never too late to learn. Let's say you're 35. Well, by the time you're 43 you'll be doing character portraits for free for everyone at the gaming table. You never have to come here and beg for one at the "The EN World FREE Character Portrait Request Thread!". Or shell out money at a comic-con art table. If you never start, you'll never be able to do it.
Its a matter of how much it means to you. I personally don't think it'll take 8 years, but you never know. I was drawing since I was in pre-school. But most of my learning is self taught. My art truly grew when I went to art college. That was when the real learning began. In those few years, I learned at a higher rate. I became a professional after than and "on-the-job" training further enchanced my skills. But I also drew when I got home from work too.
Draw draw draw draw.
One comic-book editor I met once said something like this, "Buy a stack of sketch books. Let's say, like 10 or so. Put 'em by the door. Grab a sketch book on the way out. Draw while you're waiting for food at a restraunt. Draw while you're waiting at the DMV. Draw while you're in line for a movie theatre. Draw on lunch break. When you finish one sketch book, throw it next to the other sketch books making a 2nd pile. Grab the next empty one and keep going. After about a month, look at the two piles. If the "finished" sketch book pile is only like 2 books tall . . . you're not doing enough drawing."
I had a professor who said "The first 10,000 pots are really hard, after that you get numb and it gets easier." 
