1) When to buy/sell
- Stick on to your strategy and never trade if anything went against your strategy.
- Trade with the trend. Analyze the stock in different time frames to analyze the trend.
- Stock may be showing a bull/bearish trend in the short term but the scenario may be different when we look into large frames.
2) What to buy/sell
- Invest or trade-in stocks only you have understood.
3) How much to buy/sell
- Take trade according to your position size and risk-reward ratio.
4) Maximum risk per position.
- Never risk more than one-tenth of your capital on any one trade.
5) Maximum risk of the portfolio.
If you don't have an answer yet, do research, backtest and then start trading.