When learning specific techniques to determine the dominant planet one also looks at how the d. planet then plays out in the life of famous people with whom we have facts to base our findings. There are several techniques and it takes looking at the events and decisions in your life, what planet is calling the shots, to be confident of the d. planet. Plus, not every chart has a Lord.
Here are three different approaches to determining the Lord. First...
1. Domicle lord of the Midheaven, if this planet is angular.
2. A planet in the 10th house.
3. A planet in the 11th house.
If no planets meet this criteria then there is no Lord.
Second...
1. Planet should not be under the beams of the Sun
2. Has more "dignity" in its location via sign rulership
3. Has the most power in terms of angularity.
4. Has the most power in terms of its configuration with the other planets in the chart.
Third...
1. Approach oriented to the Asc. Place considered the helm of the ship and
planets are the different officers on the ship. If metaphors suit you.
2. The bound lord of degree of the Asc.
-Co-Master is domicile lord of the rising sign
Source:
https://www.youtube.com/watch?v=Lo8gXjDEQmM&t=10224s
MD