Wow, that is a big question for taking up so little space.
The top points I look at are He-Sea points, Association points (on the dorsum), and maybe the Lower Uniting points like ST 37 and ST 39. Alarm points are also useful, including GB 25 and LV 13. Then, just the heavy hitter points for a channel, like GB 30 and GB 20 for the GB channel, as examples.
If you get a better response to BL 19 than GB 34, or vice versa, it doesn't mean a lot to me necessarily. If a major GB point has a big impact, that is enough to suspect the GB as involved, regardless which one it is.
The above are the main points I find myself interpreting. Sedating He-Sea points means drawing out excesses. For GB 34, that would be an excess level of function of the Shao Yang 'pump'. For SP 9, it would be the excess of the Spleen, which is Dampness.
ST 37 and 39 are Sea of Blood points, so usually that is what they are influencing - not so much the Yang Ming or ST channel per se.
Hopefully, that gives you some guidance.
Steve