Analysis paralysis could cost you more than a bad trade.

At some point you have to pull the trigger.
Waiting for the perfect setup:
You are never going to get a perfect entry.
You will always wish you bought slightly cheaper.
Hindsight is always 20/20.
Not starting is the biggest risk:
Staying in your day job until 70 is riskier than making an imperfect trade on a quality company at a fair price.
What actually matters:
Buy quality companies at good prices.
Keep ratios in check.
Stay in the game.
Make more than you lose.
Beat the S&P.
That is the whole thing.
You will never know everything.
Start anyway.
I lose on some trades. Everyone does.
As long as I make more than I lose and beat the S&P it is worth doing.