Tapa is the first principle of dharma. The literal translation to tapa is self discipline. Tapa is means to me that even when no one is looking you do the right thing and it also means doing the right thing at the right time. For example you should a have a set time that you try to eat your meals at every day and you shouldn't sleep too much or too little. Tapa can also mean to focus at the task given at hand and do it to the fullest of your extent,  you shouldn't do a project worse than you would do something else just because it is not graded or extracurricular etc. You also should not do something better for someone because you like them more and another person less.