A trader will typically use technicals like charts, moving averages, oscillators to catch the momentum in a stock. Then they focus purely on riding the momentum and news flows. The strategy of a trader is to churn the money as frequently as possible to enhance the ROI on the investment. They play the market on the long side and the short side.
An investor is more of a believer in fundamentals. They look at financial and non-financial parameters like earnings, growth, margins, management quality etc. Charts are of limited value for investors. An investor, basically, adopts a buy-and-hold strategy. They are not comfortable with too much churning. Rather, they would identify solid stocks and stay with them for many years.