The below habits of mine have help me in becoming a better trader.

1) Know yourself first.
Know how much you are willing to risk.
Learn what you do not know yet (fundamental and technical analysis)
Always take care of the downside FIRST.

2) Before placing a trade, decide on your strategy and your 3 points - Stop loss point, entry point and the profit-taking point. (you will know these points when you learn how to analyze the chart, it's not random, it's not gambling, it's PROBABILITY)

4) Once you're in the trade, don't change these points. For eg: changing the profit-taking point higher just because you saw the bullish trend (GREED!) The trend may reverse against you before hitting your desired point.

5) Keep a trading journal. Record why you want to trade the particular stock. What causes you to sell (fear?) Why you hold on to a losing trade (hope?)
Through this journal, you'll understand yourself better.

6) Manage your position size in every trade. Sure you can make million in a single trade. You can also WIPE OUT YOUR ENTIRE capital in one losing trade.

7) Keep reading and learning. Be patient & don't force a trade.