$150 is fine but with a small account you will be better with a broker that lets you use flexible lot sizes rather than fixed – oanda or etoro will for example. They work better when you have really small trade sizes, like $10, $20,…. You could also use what’s called a nano account, that means every trade you do is of a fixed size (the smallest size of 1/1000 of a standard lot). As Jayc Spik says you will need to watch your money management too.
Day traders use a combination of different techniques: range trading and breakout-trading are popular and are what most people start with. Hope that helps.