Tapemeasure and mirror is fine... usually blokes store around their belly, so measure that and if it shrinks but your arms/legs don't look soft or you lose strength, it's working :)
Of course if you have to lose a lot of weight you will sacrifice a bit of oomph for getting up hills a lot easier ;)
Scales that give me a number. Aware it's probably not accurate, but it's more indication than I had otherwise. I use a 7 day rolling average to smooth out the curve too.
How are people measuring body fat %?
I have scales that give me a number, but I don't trust them.