I'm going to point you in the direction of a guy called Derek Bristol, a youtube sensation. He is an American (and came over here for hidden earth) but his videos on Cave surveying are second to none.
Probably a good starting point would be his video on Sketching, this one's on Traditional surveying (ie tape compass and clino), he's far better than I will ever be.
The American's are fastidious with their surveys, if a survey doesn't meet their criteria for entering the NSS competitions then it will (apparently) be thrown out before it can even see a pin for the wall.
Therefore if you've got a few minutes to spend, then watching his videos is an essential investment (if you want to learn cave surveying).
And if you want to learn how to use the new fangled electronic equipment, then it's also a useful starting point, before Boris unleashes you onto the caves again.
There's some on each of the electronic methods:
Topodroid (a few but this is the least heavy)=
He's also got some on Pockettopo which is the other rival bit of software, and Rich's Sexy topo (for android) is most like Pockettopo.
and this is his full playlist on all cave surveying= https://www.youtube.com/playlist?list=PLxgxDxSeVuvuDXMflLV7nOYdPFroOcATVWhy I did the therion lessons first?
Topodroid is built to be integrated directly to therion, in fact I think Nearlywhite is trying to get his cave surveys so that they output straight from Topodroid, but i'm not sure how far he's got on that.
Unfortunately I don't think Derek Bristol uses Therion, so his videos neglect to mention that lines should be drawn in an anticlockwise direction (if you're looking to output that way).
and also lines shouldn't really be shaded in Topodroid, whereas in Sexytopo/Pockettopo this is fine.
This is because the integration of topodroid to Therion takes each line you draw and puts it into the software.
Whereas sexytopo and Pockettopo only pull the points into the software and leave your drawing as a backing image, so you've got to draw the walls and lines in yourself. It's all just personal preference really.