Starcraft – How to effectively manage supporting and different types of units

For protoss you have to make excellent use of Sentries to delay your enemy. If possible, try to split his army in two with Force Field(s) and take on that half by itself with your zealots, sentries, and stalkers. You won't be able to take him in a head-on fight as Marines/Marauders dominate your T1 units.

Use this delaying tactic to get a few Immortals as soon as possible and transition into Colossus with the range upgrade. The splash damage is very effective against the tightly clumped Bio Ball, while Immortals can take many hits from Siege Tanks. Use Blink Stalkers to get close to the tanks and focus them down. Note that once you have a few Colossi, your opponent will usually get a few vikings to counter them, but focus them down quickly with your stalkers.

Honestly, it is a very difficult thing to beat as Protoss if your opponent is of better or equal skill, especially since you have to tech to very expensive units just to counter his (mostly) T1 army. You'll just have to delay and outplay them and not make any mistakes, and make sure you are very proficient with your Force Field and Guardian Shield usage.

Another option is to go High Templars with Psionic Storm and Feedback on the Medivacs, but I rarely go this route as it is too gas-intensive and higher level Terran players will just use Ghosts which nullify High Templars with their EMP ability (Removes all energy and 100 shield points). Not to mention if your clump of High Templars goes within range of a Siege Tank you're dead meat.

It sounds like you're building a large army and using it to gain map control, but then are falling prey to things like drops and backdooring.

If you have map control your first thought should never be: Crush my opponent, as you're essentially sacrificing an advantage (map control) for an unsure victory (because he doesn't control the map doesn't mean he can't take you). Instead your thought should be: take the map. I think you'll find this change in philosophy will lead to situations where you have a much more powerful economy than him and you're able to kill him with attrition.

Now if you're falling prey to things like BD here is a quick check list for you:

• Are you scouting? an Observer should be the first thing you build out of Robo. If you don't go Robo, a Hallucination works just as well. Sometimes scouting means sacrificing some Zealots in a pointless charge to just get inside his base.
• If you're scouting, are you seeing it coming? Overlords on the edge of your base, Starport with Reactor + 3 Rax, all of these are indicative of certain strategies you should watch out for.
• If you see it coming, how are you responding? If you have map control that means you should be able to respond quickly. Shutting down these back door attempts is often a bigger victory than a straight up conflict
• Finally, Do you have map control? If you don't have map control that means he does, and if he's beating you with map control then your problem is not "how do I deal with a base trade?" but rather, how do I regain the advantage.