Here are 3 guidelines for new players who aren't too sure of how to bid and/or play their cards. These suggestions aren't carved in stone but if you follow them you are likely to improve your game if it currently 'stinks'.
1. Bid zero unless you have a Wizard or are void in 1 suit and have good trump cards.
2. When last to bid never make an underbid unless you have at least 1 Jester.
3. When a hand is underbid try to lose every trick regardless of how many tricks you may have bid.