5. Focus on the long-term

Stock investing is filled with intricate strategies and approaches, yet some of the most successful investors have done little more than stick with the basics. That generally means using funds for the bulk of your portfolio — Warren Buffett has famously said a low-cost S&P 500 index fund is the best investment most Americans can make — and choosing individual stocks only if you believe in the company’s potential for long-term growth.
The best thing to do after you start investing in stocks or mutual funds may be the hardest: Don’t look at them. Unless you’re trying to beat the odds and succeed at day trading, it’s good to avoid the habit of compulsively checking how your stocks are doing several times a day, every day.