I'm a beginner investor but just wondering what are some mistakes I can learn from so that I don't have to learn the hard way. What are some common mistakes even seasoned investors make?

1. Focus on business/companies you can understand. Don't stray from your circle of competence unless you have read up and understood more about it.

2. Ignore the noise; everyone online/around you might tell you to buy this or sell that. If you do your own due dilligence, you'll make the final say. Have conviction in your stocks instead of listening to others. But if you think you have made an error in judgement of the company you are looking into, don't be afraid to sell and redeploy to better stocks.

3. Think long term. If the companies you hold are great, let them grow and compound the money.

4. Time in market over timing the market. No one knows when the lowest or highest point is. Buy when the valuation is sound according to you.

Not doing enough of your own research on the fundamentals/financial health of the company you are looking to buy (if you DIY/stock pick that is)

Allowing fear to cause you to question the research you have done, and prematurely taking profits when price increase / selling out when the price drops.

Waiting "for the right time" to enter, don't trust my own research and instead listened to the naysayers. Experienced this first hand, missed the uptrend. Powerful lesson.