What’s the best way to do it and have them remain there? Thats the typical use case – sometimes I want to have a test point so I can view a waveform – sometimes its to extract a timing signal, mostly just a one time thing. I would like to know how to do this better.
Currently I use teflon coated or magnet wire, I try to tin just a tiny bit, I use lots of flux, I inspect afterward in microscope. The problem is the area available for soldering is often really tiny.  Typically I’ll succeed but then the wire just doesn’t stay in place, nomatter how well I fasten it. 
For example, I have one board that needs to have two tiny wires connected to a chip and that space is just almost nothing. Its very difficult to get it to stick for good. Even with hot glue anchoring the wires. 
Are there any products designed to press a test lead to a specific spot and hold it there that don’t cost an arm and a leg?