Battlestar Galactica: How to balance core game
From page 28 of the rulebook:


  To make the game easier for the human players, start the game with 2 more of each resource (10 food, 10 fuel, 12 morale, and 14 population).


However, it's worth mentioning that the core game is very balanced, especially with 5 players. The expansions arguably make it more difficult.

It sounds like you're not playing very well, but it's difficult to offer suggestions without knowing more about your group and how they play. You should be analysing everyone's moves and motives and closely inspecting the results of all skill checks. The Cylons should feel pressured to help out at every opportunity, lest they be accused and possibly brigged.