How do you calculate the odds of something occurring if you have two bites at the cherry? For example you have a four flush in hold'em with two cards to come.

The most accurate method is simulating the situation on a computer and running it many thousands of times. Mathematically it can be done as follows:
Probability of winning =
1 - the probability of not making it the first time x probability of not making it the second

You hit the flush about 1 in 3. Thus you win 1 - 2/3 x 2/3 = 5/9.

All gambling involves luck. While luck tends to even itself out over the long run, people naturally focus on the short run and on their fluctuations.

Because gambling involves randomness, people will often blame or chalk up their luck to some random event that coincided with how they fared at a certain gambling session. This may be as innocent as believing in a lucky shirt. However, some people take these superstitions too far. They start to believe that if they constantly move seats or change their socks that they will somehow become the next WSOP winner.

You cannot affect the 'luck' factor of gambling. Luck evens itself out over the long run. The only thing you should concern yourself at the poker table is playing well. If you play very well at poker, you will win over the long run. If you do not play well, you will lose. It's as simple as that.

In what other activity other than poker can you take $30 and parlay it up into a $5 million jackpot by skill? But it ain't easy and it takes time.

First you play in an online tournament which gets a seat in a satellite, which would otherwise have cost you $210 to enter. Then you play the satellite and survive perhaps 10 hours hard grind to win your place in the $10,000 buy-in World Series. Then you win the World Series.

Unsurprisingly, if you succeed in doing so, you have won an extremely odds-against parlay. Perhaps it was 25 million/1. But the odds were fair and the percentage taken by the organisers very reasonable. Also, don't despair if you fail to win the event, finishing in the top 10 should provide a life-changing win for most people.