My small (12 Kingdom card) fan set, Enterprise, holds up pretty well to these criteria. Of course, that's not a coincidence. I tried to make sure I had a good balance of these factors when I created the set.
1 card that let you play more than 1 Terminal Action: Mill Town
2 cards with +Buy: Fund, Inventor
1 deck thinner: Gambler
1 remodeler: Exchange
7 one-shots: Surveyor, Gambler, Boycott, Enforcer, Conscripts, Exchange, Fund
1 junker: Conscripts
1 discarder: Tax Collector
1 trasher: Tax Collector
1 deck mucker: Enforcer
The only place it falls short is in cards that let you play multiple terminal Actions in a turn. I could add an extra +Action onto Exchange, I guess. The only other easy option is adding it to Barracks, and I've found +2 Actions isn't so hot on a card that gives Curses (in a roundabout way).
As for the article, I'd also mention having a good mix of terminal and non-terminal Actions. Many fan sets fall into the trap of having almost exclusively non-terminal Actions. I think a good ratio to shoot for is 1:1, but there's a lot of wiggle room there. 2:1 or 1:2 isn't unreasonable.