HOW TO: Create Mouseover Macros in SWTOR!
I use a G15 keyboard for this, but it can be done with AutoHotKey or other software macro tools that are available.
Mouseover macros can eliminate targeting clicks, and greatly speed up your actions in both PvE and PvP environments. It can be especially useful for healers in Flashpoints, Warzones, and Operations (or any situation that requires constant target switching and healing/support). Consider how often Sorcerer and Operative healers change targets when throwing out HoTs and shields in a 16-man Operation.
Healing Mouseover
This trick is simple, but remarkably effective. Just create a macro in your Keyboard Profiler that simulates a mouse click at the current mouse location, and then presses your desired ability hotkey. Here is a screenshot demonstrating a basic macro I use to easily cast Lightning Shield on my allies:
I mouseover the frame or model of the player I want to cast Lightning Shield on, and then I push my G15 hotkey. The macro clicks the mouse to select the target, and then it presses 1, which is my keybind for Lightning Shield. The 10ms delay is there because of lag, and it may not be necessary on faster machines. I also use the 'repeat while pressed' option, so as long as I hold down my G15 hotkey, the macro is spammed and all I have to do is move my mouse over my party members' frames to cast it on everyone.
Offensive Mouseover
The same concept can be applied to offensive mouseover macros, where you want to quickly target an enemy and interrupt or CC him (extremely useful in PvP). Here is an example of a macro that casts Jolt (interrrupt) on whatever enemy my mouse is hovering over, and then returns my target to the previous enemy (in theory; I'm not exactly sure how the Target Previous Enemy command works in this game):
As before, the macro clicks my current mouse location, waits 10ms and then presses 2, which Jolt is bound to. Target Previous Enemy is bound to Backspace, so if the command works like it should, the guy my mouse is hovering over (enemy healer) just got interrupted, but I'm targeting my kill target again. The Jolted healer just stands there, watching me fry his teammate to a crisp.
If anyone can provide a AHK script that would accomplish this same task, I would be happy to add it to this post.
Hopefully other players will find this as useful as I do. I've been benefiting from the OwnedCore/MMOwned community for a couple of years now, and I hope I can give a little back.