Bitcoin trading is on of the best way for making profit by using of buying low and selling high. There are two main methods for gaining from the market also people always use to analyze Bitcoin price first on is fundamental analysis and second on is technical analysis. Every successful trading requires a lot of time, money and effort before you can actually get good profit from the market. So you need to learn which price you by and which price you sell using your analysis.
What you are trying to do is to time the market and many end up doing the opposite of what is desirable, as @TheUltraElite has commented. It's better to buy and hold for the long term, minimum for one cycle and never sell all your Bitcoin. It doesn't make much sense to buy and sell the most profitable asset in the short term. It's better to focus on the long term.