Today I learnt valuable lesson which I would like I knew before and would like someone has told me.
Today was start of TenX ICO at 3 pm CEST. Instructions on how to invest Ethereum said how many gas and gwei you need to put for transaction to be confirmed. As you probably know, this was one of the most crowded ICO until now. It was done in 8 minutes. I expected that, prepared my transaction on MyEtherWallet (MEW) and when clock ticked on exactly 3 pm, I created transaction. And then it started. Ethereum network got congested and my transaction was pending and pending and pending. In the backlog you could see enormous amount of other transactions also pending. Then, I did something no one ever told me, just to try get through. I raised gas limit and gwei and tried to do transaction again. And it got through immediately. I later on read about this problem and people complaining about instructions not being cleared, but that were just recommendations and not something that was written in the stone.
Valuable lesson is:
If you want your Ethereum transaction to get through in crowded ICO, increase gas limit and gwei. Yes, you will pay somewhat greater fee, but increasing it just for a bit, you are in front of everyone else who followed instructions. And you will get your valuable coins.