I think in order to practice compassion and emptiness we must meditate first using calm abiding and then later adding special insight meditation. Doing this will bring us to the realization that everything is empty of an inherent existence and that form is no different from emptiness and emptiness no different from form. Meditating will also open up our hearts and we will be able to meditate on equanimity, love, compassion and joy. Then we can also use the meditation of taking the suffering of others on ourselves and exchanging it for our own happiness and what makes us happy. In between meditation sessions we must put compassion into action by always putting the interest of others before our own.