your units out of sight, and then stim & run them in to hopefully destroy the building in question, since the player not having enough time to react is the key. Mineral line harassment is just killing workers and moving them away from the mineral line. If you don't know already you can drop units while the medivac is moving if you select drop then click on the medivac (which is preferable for mineral line harassment drops); Tip 3: TvP: Always Scan Before Moving Your Army Out The Protoss Observer is a very strong unit, it gives them so much vision and knowledge for a cheap price, you should kill them whenever possible so they don't have an eye to see exactly where your army is. You should scan especially just before you decide to move out, since that is where it's important for the other player not to know where you are. Always get into the habit of scanning before moving out, write a sticky note if you have to- you certainly don't want the Protoss to be prepared, TvP mid/lategame is hard enough without having to deal with maphax. Tip 4: Marines are Cheaper Than Scans Unfortunately for the poor marines, they make for much better scans as suicide scouts than a scan. A marine is only 50 minerals and is very fast when stimmed- it makes for a much more cost effective scouting method in the mid to late game. You save a lot of mules by