Making photosets is easy. Here is an overly detailed explanation of how I do it (I need a distraction while my game loads) :
To find images, I simply use Google. Obviously, you’ll need to know what kind of stuff you’re searching for, and make good use of the extended search tools. Getting creative with keywords can also have you stumbling upon interesting pictures. Personally, I like to find my images before I assemble the photoset, and save more than I’ll use. It saves me the trouble of having to look again if something doesn’t fit.
Once I have all the pictures I need, it’s a simple process of arranging them on a basic photoset template. Which means choosing what images’ll look best, cropping and resizing them, making sure the full set is visually balanced (mine sometimes aren’t :p), etc. Then comes a lot of colour tweaking (matching your pics’ hues, then playing with the overall colour(s) of the set). Having good colours is important; a nice scheme will really set the mood. I like to have two main contrasting colours in my sets, but having a few more, or just one overall hue can also work.
Annd I think that’s it. I’ve said a lot about little already :p
(And now I’ve regained my inspiration to make photosets, yay! So I should finally finish the Beaker one, then do the Smiths and the various TS2 hoods.)