[faithHunter]

Originally Posted by soyabean45

I like to go bio but they all camp and shell my natural away.

Could you possibly be talking not about the unit composition, but rather about the 1-1-1 Marine Tank Banshee timing? If that is the case, assuming you went 1rax FE, you should have a factory up and a handful of marines, with a starport building and combat shields finished/almost finished. When you see your opponent moving out, try intercepting them with your marines and try to snipe dem tanks. Meanwhile back at home you should work on getting siege tech for siege tanks and placing the tanks out of range of your opponents's tanks while covering your natural. He should pull back once he realizes he cannot do any more damage.

If you ARE talking about the unit composition, biocentric play is very very mobile, while mech play is very immobile. To hold map control as a mech player, they will usually just siege a couple of tanks at a spot to hold that spot. They will also make turret rings to deny drops and place vikings at the perimeter.

You should be aggresive as the bionic player. Snipe undefended or lightly defended expansions while forcing him to just run around the map and hold his part of the ground while expanding literally everywhere behind your aggression. Beware of hellion run bys tho. In the lategame though, you need a couple of tanks to hold your ground when he's about to do his mech push.

When engaging the mech army, try flanking or carpet bombing their tanks with marauders while their vikings are out of position. You can also try avoiding his mech army and forcing a base trade. You should have more bases than the mech player if you played correctly, that way the base trade scenario will be in your favor.

That's all I can say about engaging a mech army though. You should upload a replay so that we can see what you did wrong or what you could do better.