Let us use some common sense ideas to identify what a bullish bar may look like.
When the market closes above the previous close the message is of strength.
When the market closes above the open of the day, again a message of strength comes in.
When the market makes an intraday low, recovers from the low to close higher, thus making a long lower shadow, the pattern would be considered bullish because a test of low probably took place.
A pattern that is not bullish is a candle with long upper shadows.
The best way to enter the market after a bullish candle is to wait for some sign of strength. When the market trades above the high of the bullish candle such a sign is available.