Checklist :

1. The pins DB0 to DB7 of the LCD must be connected to pins 0 to 7 respectively of the data port. Do this to avoid severe
   headaches during programming.

2. The RS, R/W and E pins should be connected to pins 0,1,2 of another port, preferably in the same order for programming
   convenience.

3. Make sure you have given correct power supply everywhere.