Strongly recommend laddering your buys as @haejin suggest. What it means is never spent all your capital in one buy, segregate it into smaller chunks. So if you have $500, you can divide it into 4 parts of $150 each and buy Bitcoins at 4 different price levels. You can find his tutorial on that topic. All the best.
https://steemit.com/bitcoin/@haejin/an-effective-buying-and-selling-strategy-laddering-a-tutorial-on-to-cast-a-ladder