You must have basic knowledge and skills for buying and selling which are helpful for your investment but don't use buying and selling for your trading. At least you must use Buying and Selling orders without mistakes.

Market Order vs. Limit Order: What's the Difference?

Investment is better and safer than trading and if you invest in a safest cryptocurrency, Bitcoin, you will have profit. If you invest in altcoins, I am not sure about how you end with them. Most of altcoins will bring losses to you, not profit because most of altcoins die with time.