I found a great excerpt from this article on UX Planet!

“The fundamentals for passing the UX test: remote and face-to-face

To pass its usability tests, whether remotely or face-to-face, certain points must be taken into account:

• Limit yourself only to the testers of your target: you must respect the target of your website so as not to distort the results; especially when its field of activity is very specific and concerns only a minority of people. It is therefore enough to refine your search by limiting yourself to the circle close to your network, by calling on customers, prospects, or by calling on an external panel.
• Get closer to the user: understanding the tester and justifying all their remarks is essential. You have to show empathy and take into account all user feedback. Be careful, however, not to draw hasty conclusions as soon as a user returns. The results of the tests are to be put into perspective with quantitative data and UX expertise.
• Focus on design responsive: during the implementation of the user testing process, we must think to apply it on all resolutions, namely the smartphone, the tablet, the desktop computer, the TV, or others. The layout of the buttons, the tactile use, and the usage scenarios are different on each device.
• Quantity does not matter: Jakob Nielsen, an expert in the field of computer ergonomics and the usability of websites, states in his article Why You Only Need to Test with 5 Users that 5 testers (per user segment and device) are the ideal number for successfully obtaining an optimal usability test result. Quality is obviously more important than quantity.

Conclusion

Remember that UX tests, whether face-to-face or remote, have their advantages as well as their disadvantages. To succeed in making the right choice, it is enough to take into consideration a few factors, including the number of participants, the budget, the deadlines and above all the objective of your site or digital product!”