Kittens, kittens, oh egad, how I love kittens!

They're so adorable and so much fun! But so much work!
You need this book:
Think Like a Cat: How to Raise a Well-Adjusted Cat.. Not a Sourpuss by Pam Johnson-Bennett. You need it BEFORE you bring kitty home.
You need to think about and plan how you're going to introduce her to your home-- I recommend starting small, with a single room, and gradually introducing her to more of the house over a few weeks.
You need to think about discipline, and have your game plan in place from day 1.
You need to think about kitten-proofing your house. Toxic substances, toxics houseplants, things she can tear up, knock over, swallow, etc. need to be removed or put out of reach.
Other than that, there's nothing to it!

PS: I agree, two kittens are twice the fun, keep each company, and aren't significantly more work to take care of. I have three, and I NEVER lack for kitty love-- sometimes I have more than I can handle!