I ride a Brooks. For keeping the leather in good shape, they sell something they call "proofide". It's ridiculously highly priced, but a little goes a long way, so I just use it, mostly because the saddle cost enough that I don't want to mess it up. Plus, my butt really loves it.
There's both the lacing and an adjustable bolt that you can use to tighten things up. Don't over-tighten; that will just stretch the leather. I keep my laces tight enough that they resist widening when I sit on the saddle, but not so tight that they stretch the saddle when it's unused.
I have no idea if I'm actually doing it right, but that's what works for me.