Many users here are talking about highest peaks, to sell high, buy low etc. It sounds easy but it's not. Everyone knows you should buy low, sell high but most of unexperienced traders doesn't know when is the right time to sell or buy. So how can you be sure when the price is high and it won't go even higher? Or when the price is low that it won't go even lower.
You could never know that 100%, but you can help yourself with tehnical analysis with some combination with a fundamental analysis.
Those analysis are not correct all the time but if you have some TA experienced trader you could predict important lines and make some important trading moves based on that. I like to swing trade. It's less stressfull than daytrading. But daytrading can be fun too