EDIT: By request, I posted this as a deviation. Thanks for your responses!
The Big Secret to Learning How to Draw:
In the Beginning... You see an apple, and you draw an apple. You look at your drawing, and it's utter crap. It looks nothing like the real thing, and you wonder why. "Hey, a real apple is red and round. My drawing is red and round. Huh. What's wrong?"
You draw some more apples. Many times.
And finally, one day, you have a Eureka! moment. You realize, *d'oh!* a real apple isn't entirely round! It's wider at the top, narrower underneath. It's got funky little lumps at the bottom. It's got a dip like a crazy deep belly button at the very top. You draw another apple. The result is better, but it's still crap. Much nicer crap than before, but still.... Hmm.
You draw more apples. Repeat.
Another day of drawing, another Eureka! moment. Hello! The red isn't really red. This particular apple is slightly darker than true red. And it's got some tiny tan spots on it. And at the top, the red turns into a pale green color near the stem. You draw an apple once again. And hey, it's getting close, but still not quite there. And you wonder why.
So you keep drawing and drawing, blah blah, repeat.
And one day, after you've been drawing apples to the point where you never want to eat an apple ever again, you realize.... Holy crud! The redness of the apple shifts with lighting! There's a circular white spot for hard light sources. There's a softer, fuzzier light reddish orange spot for softer light sources. Back to the drawing board. The apple drawing is getting pretty good now, but still not quite right. Geez, how long does it take to learn to draw a friggin' apple anyway?
Blah blah, more drawing....
... Texture! You forgot texture! Little bumps on the surface! It's not perfectly smooth! Aha! But...how to draw those bumps? Hmm.... Oh! Those bumps show up as color shifts! You mix some lighter reds with the subtle, darker red splotches. You break up the highlights a bit so that they're not just round white circles. They're slightly irregular circles, and sometimes they have little satellite circles surrounding the main highlight circle. And while we're at it, those green streaks near the top of the apple sometimes spread out a little in a star-like pattern, although it's really faint, and the color at the tips of the stars look more orange or yellow than green. And hey, since we're looking closely, this apple is so shiny, you don't just see highlight from lights on it. You can actually vaguely see a reflection of the rest of the kitchen on it. The shapes are really vague and they don't affect the color much, but they're there. Just a slight hint of shadow on the apple surface. And oh! The apple is on a white table, and the reflection of the table is visible on the lower half of the apple as a hint of lighter red. And at the edge of the apple, that reflected color is a bit stronger so that it actually causes a near-white outline on the bottom half of the shape of the apple. Woaaah, never noticed all that stuff before! Seriously, there's hardly a single large spot on this apple that is uniform in color! So much to think about in such a simple object! (And at this point, your roommate walks in and wonders why you're staring at this apple, titillated, like you just met the love of your life.)
So now, you can draw an apple wonderfully when you're looking at it. But you go to draw it without a real life model or a photo reference, and it looks like crap again. *headdesk* So what's wrong?
Uh-huh. You don't know the apple as well as you think you do. So you go look at more apples, and you obsessively try to memorize them. You study different kinds and note how they vary in color and shape. You compare to see how different apples are similar to each other, and how they're completely different.
Meanwhile, you keep drawing apples.
And one glorious day, you realize you can draw an apple from memory, and it looks pretty damned good! Yay!
... And then you realize YEARS have gone by. D-:
It didn't happen in a day. It didn't happen in a week. And you are disheartened, thinking that you must be the world's biggest idiot if it takes you YEARS to learn to draw a stoopid apple. (Never mind a more complicated shape like a human! Or a human in a dynamic pose! Or a human in a dynamic pose standing in front of a crazy background with nutty perspective! And multiple light sources! Aaaargh. Time to crawl back into bed and never come out. Ha ha.)
But I digress....
Yeah, why did it take so long to learn? Hmm. Maybe all along, while you were drawing them incorrectly, your brain was slowly learning and assimilating and percolating. And part of the process is to collect bits of data and munch on them for a bit. That mental munching takes time. And without the time, you wouldn't have had those Eureka! moments because your brain wouldn't have been ready to make the leap just yet.
The years you spent, they have nothing to do with how simple the form of an apple is. They have everything to do with developing a different way of seeing the world. Seriously. Congratulate yourself! You didn't spend years learning to draw a piece of fruit! You spent years learning how to see in AN ENTIRELY NEW WAY. And learning a new way to see is quite an accomplishment. Because now, if you want to draw something else, like, say, a banana... You won't have to spend years learning it like you did with the apple. It'll only take a short amount of time to learn because the groundwork has already been done. Your brain knows how to approach the task now.
That new vision is what takes time. And that new vision and understanding is what you can't get just from mindlessly reading a book or doing a tutorial. Those resources can help, but only if you put forth the effort and actually bother to think while you're using them.
And sadly, so many people don't seem to get it. They think there's some Ultra Secret Shortcut to learning how to draw. If a tutorial doesn't help, they think they're simply using the wrong tutorial, and they go off in search of the right one, not knowing that they'll probably never find it, and they'll just be disappointed.
And all along, the answers are in their own head if they'd only put in the effort and the time. But hey, some people can barely wait 5 minutes for a burger at the drive-thru. Asking for years of dedication's just absurd. Especially when you've got Wonderful Things like Photoshop and Magic Tutorials. Right? *..... sigh.*