I've been working from home for the last 5 years or so. The best tip I can give anyone is to "act" like you're at an office.

I set up a spare bedroom as an office. I have it set up like an office, and I keep non-officy stuff out of that room. I get dressed for work every morning in casual attire, but I impose a personal requirement that my shirt has to have a collar (usually a polo). I keep an open Skype channel with my remote office as frequently as possible, even if I'm not talking to the person on the other end. The sounds of an office on the other side help me keep the office mindset.

Basically, I solve the problem by pretending that I'm in an office. Maybe that's silly, but it's worked really well for me.