General advice:
Play base game or base game + Daybreak only.
Play with five players. Two You Are A Cylon cards, eight You Are Not A Cylon cards (one more Not-Cylon for Baltar and Boomer).
Remember that the goal as the Humans is to have the resources survive Crisis Cards (and Cylon treachery) until reaching Kobol.
On your turn, you may move to one location on the board and then you may take one action (from your hand/special abilities/board location/etc.).
The default actions should revolve around scouting the Crisis Card and Destination decks (Launch Scout, Boomer's end-of-turn power, Roslin's Crisis Card power) and making sure the humans have enough skill cards to pass important skill checks (Press Room location); Investigative Committee should be played often to aid skill checks. Human players should be Executive Ordering each other pretty much all the time to increase the total number of actions taken. The only other actions that should be taken are very situational (FTL Control location on the last space of the jump track (-1 pop) and population is not important or FTL Control on -1/-3 when Cylon ships are an extreme threat; Repair when important/many locations/Vipers are damaged; Admiral's Quarters location when the majority of players are prepared to brig a Cylon; etc.).
Try to have at least one but no more than two pilots. The pilots have two special tasks:
1. Protect Civilian Ships from being hit by Raiders (stay with the Civilian Ships, play Evasive Maneuvers as necessary)
2. Prevent Heavy Raiders from boarding (Maximum Firepower when Heavy Raiders reach docking locations)
Most of the time neither of those needs are pressing. This does not mean the pilots should fly around blowing up shit just for the heck of it. Instead, the pilots should be playing Executive Order and/or Launch Scout. If Civilian Ships are placed in multiple locations, Human players should use the Communications location to consolidate them into a region defended by the pilot(s).
In short, make liberal use of Investigative Committee, Launch Scout and Executive Order.
As a Cylon, your goal is to deal maximum damage to the Human players. Staying hidden is not your goal. Ideally you want to be able to deal ongoing damage (causing multiple skill checks to fail, sowing dissent and distrust), massive damage (spiking important skill checks, moving Civilian Ships into the line of fire) and Reveal before being brigged, but you should take what you can get. Too often I've seen Cylons play pro-Human the entire game because they're afraid of being caught. That's how the Cylon team loses.