Well, my method is probably backwards, but hey, it works for me.
I am the "Great Defender" of unloved crappy cards, and I find strange and unusual ways to make decks out of them. These very Rogue decks are lots of fun, and I am finding they work way too good sometimes, so new synergy is possible from almost any card.
For instance, I liked those very unloved Urza's lands, Urza's Mine, Power Plant and Tower that make colorless mana, and make double and triple if you have all 3 in play. I made a deck of all colorless and artifacts (and a bit of blue, because I added in Tolarian Academy) and it kicked. It frustrated everyone I played against, even those who had Artifact removal or Land destruction decks, because the mana ramped up way too fast, and with additional artifact mana, you can see the fun and the frustration.
I really didn't push the Blue, or I think this could have been more maddening to face then the standard "Academy" decks before it got banned. I took it apart rather then get to power crazy...
(Don't be seduced by the Dark Side, Luke...)
Currently, I am playing what some of you may remember is my Pesky Critters deck, using most of the critter generators for Cat tokens, Snake Tokens, Squirrel tokens, Beast Tokens...etc. About the only one I don't have is Saproling Tokens, cuz I'm kinda biased, and had plenty of other token makers. In it's last incarnation of like 85 cards, it still worked too well, I'd make tokens, and then either overrun or use Coat of Arms and win. I just had a "Pro" friend help me pare it down to 60 cards (61) and I am now just testing the new deck to see if it has lost any of its fun or synergy.
I suggest you take a game mechanic or card or creature you like, and run with it, and then keep looking thorough you cards (and at the cards you opponents play with) for new ideas to improve you deck--at the least it is a lot of fun to be Rogue, and it confuses you opponents terribly.
Sorry for the long post you all, wake up now!!!