Here's probably what works the best in my experience.
Make lings and flank him if he tries to leave his base, If he does leave his base by the time he finally gets out you should have mutas unless your problem is speed. Use your mutas to attack the marines as they are built and coming out of his barracks, or to take stabs at his wandering depot's. Muta harass is only useless if you aren't aggressive and smart about it. If he does in turn mass up enough units to push out and properly avoid much harassment in his main you SHOULD have lurker tech by then and be looking to meet him somewhere from (the middle to his base) the closer you engage his units with lurker to his base the more time you have to prepare.
Don't waste groups of units needlessly, conserve your units. Pull back and when your backup comes use flanks.
By this time the terran will be looking at expanding, so his units will 70% of the time be by his choke or at the top of his ramp. Use lurker drops in the main base to harass the mineral line or depot's to slow his production.
All the mean while you are expanding and taking the map with each deadly blow you deal. Remember to upgrade in any matchup as late upgrades just don't cut it.