Firstly, start off your table in http://www.tablesgenerator.com/.
Tables Generator will do a lot for you. Its most useful features are importing from .csv and merging cells. The Booktabs table style (alternative to default table style from the menu) looks a bit nicer and is “publication quality”. Note that publication quality tables should not contain vertical lines.
Code #1 is the code from Tables Generator with the addition of caption, label and Latex document begin-end (so it’s compilable).