I'm new and just starting to figure my way out around the site, but one thing that I seem to encounter a lot and can't figure out how to do is set a diet. So what exactly is a diet, what does it do, and most importantly, how to I set up a diet composition for a pet?

I feel like I have missed something really obvious... ^^"

A pet's diet affects a pet characteristics.  Each type of food is used to help out each type of characterisistic. If you hover over the question marking next to Diet Composition on the pet page, you'll see which type of food alters each type of characteristic.  

For me, personally, I organize by which characteristic is the lowest, so that when the pet is fed, it has a chance of getting that characteristic to be level with the others.  I'm not sure by how much each characteristic is raised when pets are fed, but it's probably only about 1-3 points or so.  

All you have to do is click on the stars to set up the diet.  Then a save button will appear at the bottom and you'll click that when you're done setting it up. c:

Oh!!! I'm such an idiot. XD Thanks for helping me. ^^