First, you should determine whether you want to buy or sell.
If you want to buy, you want the base currency to rise in value and then you would sell it back at a higher price. In trader’s talk, this is called “going long” or taking a “long position.” Remember: long = buy.
If you want to sell you want the base currency to fall in value and then you would buy it back at a lower price. This is called “going short” or taking a “short position”. Remember: short = sell.