But I'm here to show you an easy way to achieve all sorts of vectorish art without difficulty.
Normally, said first step would include erasing out the background of your cap or picture. But since I'm in a highly lazy mood, lets pretend that I did this and just ignore the background, yea? But all of you should definitely erase out the background, yep. It is easier at this stage than at any later ones...
Our next step is to fix the base. sheesh. If you don't know how to do this, then you're in the wrong tutorial. I just copied and screened the base a couple of times, maybe threw in a soft light layer... but when you're done, merge the layers!
Now, we're going to use a fun filter! One that I use on almost every header I made, because it does all the smudge and blur work for me. Stylize -- Diffuse -- Anisotropic.
Duplicate your base, and turn off the visibility of one of them. I don't really care which.
Gradient maps are your friends! If you don't know what they are, click H E R E to further your education. Put in a black to white one on top, effectively desaturating the image. I do this for reference purposes... but its not neccesary.
The desaturation helps with the next two steps, the first of which would be a brightness/contrast adjustment layer. I set mine to nearly +62, but it really doesn't matter where you set yours. If you did the original base adjustment right, you shouldn't have to alter too much right here.
The next step is important! Don't skip this!
Make a new threshold adjustment layer. It will automatically pop up with a threshold level of 128. I recommend changing this. Depending on the level of detail you want, you should either lower or raise the level. Since I'm lazy, I'm not going to be doing anything fancy with this, but you could mess around with multiple threshold layers and blacked out masks to get different threshold levels for different areas, like the picture in my info. Just paint over the areas you want to use a different threshold for in black on the adjustment layer, and make a new threshold layer! Experiment! Its fun.
The desaturation helped me to predict what areas would turn black and what areas would turn white... which, I must admit, is useful. At least to me. It also makes minor changes, but feh.
The next step is to merge visible layers.
Yes, I know it feels a little scary, but as long as one copy of your base is invisible, it should be left alone.
Now, hit Ctrl+F. This will reuse that exact same diffuse filter we used so long ago. Of course... you could go the long way through to do it again, but why bother? There aren't any settings that need to be changed ^^. The repeat of the diffuse filter gets rid of a lot of the jagged edges in the threshold merged layer.
It already looks pretty damn decent! From here, you could use any combination of coloring methods. You could cut out the white or the black pieces so that you can see the original base, or you could hand color, or whatever.
But the whole point of this tutorial is to speak to the laziness in all of you.
New gradient map, on top of the merged base. I made mine a teal to yellow one. Never fear; just because its two-toned right now doesn't mean it'll stay that way.
Now, move the invisible base up to the top. From here, I usually duplicate it again and desaturate one to mess around with whichever looks better. Set this layer to any mode you like, depending on what effects you want! Here's what some of my experiments ended up looking like...
And that's all, folks. Be fruitful and multiply. Better yet, show me what you do with this knowledge!
P.S. Because the reader I was making this for complained, here's an example of what you can do when you erase out the background... which usually improves it ever so much.