Play back your edit at a very low volume on your monitors. Works especially well if you have a heavy hitting mix. If it still has the weight when played back low, you’re on the right track. If not, start tracking down where it’s not translating.
If you have cheap speakers (TV, computer, laptop, etc…), check on them too. I love this app called “Airfoil”. It lets me play protools (or any audio – it taps the audio bus) directly to my laptop, iPhone, airplay devices, etc… Very useful!
A fun trick to do is to put a bandpass EQ on your master bus to simulate the frequency range of a mobile device. You can have it on bypass and only enable it for quick mix checks. Devices’ ranges will vary, but a good starting point is a HPF at around 800Hz and a LPF at 7kHz. If your mix still sounds intelligible and punchy, you’re probably safe.
Nothing beats the real thing, of course.