First, here is a copy of The Evil Overlord's Guide. Very much useful information to be gleaned there.
One of the common misconceptions that the good have is that they will ultimately win, because they're good. Rest assured that this is nothing more than ego-stroking and can be used to your advantage.
The good often have a 'code' of honor. Ha! The fools! This is their greatest weakness, and must always be exploited and used against them. Many will constantly try to save their friends, feel the need to keep their word, obey the law, and not use any more violence than necessary. Be sure to use these weaknesses against them. i.e. "Well Jack Morgan, you can either save the city from the thermonuclear device I have set or bring me to justice! Which will it be?" They'll choose the bomb every time, leaving you more than enough ample seconds to escape in your secret hovercraft.
Note: Some 'evil' people are known to possess these codes of honor as well, particularly stereotypical chinese masterminds and guys with thick European accents. Try not to fall into the same trap, because it really hampers your style. For example: "You did well, MacGyver! You managed to escape my maze of death! I won't kill you... this time." I mean, what the hell is that? Kill him for god's sake! He's only going to come back next episode and thwart your plans!
Also, when revealing your complete master plan to the 'good' heroes, who happen to be struggling against your bonds frantically while you deliver one long big soliloquy about how well things are going exactly according to plan, don't be too surprised if they escape and then use that information against you. I mean, come on, what did you expect?