The second piece of advice is that no one experiment is going to be perfect, and because of that, you should try to design a series of experiments that reinforce each other.
I yisiyalo sesibili siwukuthi akekho experiment omunye abazobe ephelele, futhi ngenxa yalokho, kufanele sizame ukuba aklame uchungechunge ucwaningo ukuthi baqinise nomunye.