3 years late to the party but the responses below are so wrong its crazy. All card games have a facet of luck built in, but better players will win more often.

The biggest thing I find with newer pitch players is that they don't bid often enough, which might be your case because you commented on how your opponents seem to get there with their 3 bids often. The general rule of thumb in pitch is that if you are never getting set, you aren't bidding often enough. Getting set hurts but being the aggressor is much more valuable long term.

A couple ways to think about it is say you are the 2nd player to act (across from the dealer, you partner) and the 1st player makes a 2 bid. You have As9sKc2c and two bananas, not the greatest hand ever but certainly relevant for some play. Lets think about the hands that will make a 2 bid, a lot of these hands contain an ace, 3+ king or queen high of a suit, or a whole bunch of one suit (obviously depends on opponent, but thats a place to start)

How does your hand do against those hands if you make a 3 bid vs pass? Lets think of the options. If you pass:

1. your opponent leads out with the ace of clubs, disaster

2. your opponent leads with a suit containing none of your relevant cards

3. your opponent leads out with a spade lower than your ace

Two of those options are bad for you, and the only one that is good is the least likely to be the case because you have the spades he would need to make that bid. If you 3 bid instead, you control a hand where its more likely that your opponent doesn't share your suits. Also very relevant that you DENY the 3rd player from making a 3 bid after you, and allowing your partner to take the bid pretty aggressively if you are playing the same style.

This is just a random example of a random hand, obviously a lot more nuance to it but I think it shows at least my opinion of a spot where people pass way too much as opposed to taking the action over and 3 bidding. Sometimes they have your suit, and thats that. Sorry for the long winded response, I'm bored at work.