The setup here is largely based around Function Keys, then I add modifiers for apps and tasks related to the primary Function Key usage. For example,
F15 on the Apple External Keyboard launches my primary text editor, Command-F15 the app I use for checking the word count in the text editor.
F12 launches Mail. Command-F12 gives me a KM palette for selecting among a bunch of commonly needed preconfigured mail messages.
These get pretty deep, to the point that I probably have access to 50–75 apps or tasks tied to the Function Keys.
The exceptions are F1 and F2. F1 always takes me to my primary working folder in the Finder, and F2 is for a Keyboard Maestro palette of my most common KM-based actions for a KM Group tied to whatever is the frontmost app. This keeps me from ever having to remember the hot key for a primary app-specific palette.
Somehow I remember it all even though it would be useless to anyone else. For anything else app-launching-related, Spotlight is ample for my minimal remaining needs.
For a very long time I used hotkeys beginning with the modifier control key and the first letter of the name of the application.
Ultimately, I realized that it was more difficult to remember the hot keys than it was worth. The benefit diminished as the number of hotkeys increased. What I do now is use one hot key to bring up Spotlight, and then from there I simply type in the first couple of letters of the application. I use Alfred for this, but the native spotlight app works exactly the same way. It's incredibly fast and much easier than you would think.
In my opinion the use of hot keys to launch apps is fine if you only have three or four to remember. Beyond that, it takes too much mental bandwidth to try to remember the correct combination. To be clear, I am an avid KM user, but there is a time and place and tool for every purpose. In my opinion, KM is not the right tool for launching apps. Just my 2 cents worth of advice.
I use Cntrl and the first letter of the app name. For apps with the same first letter, I'll use the 2nd or last letter for the lesser used app to avoid having to use the conflict pallet step. I've used almost the whole alphabet and really don't have any trouble remembering. For lesser used apps, typing the first few letters in Spotlight I find to be the quickest way to launch them.
A good tip with the Conflict Palette method is to name the Macro that launches your most used App with a ↩ at the front of its name and give all the Apps beginning with the same letter (for example "P") the same hot key for example, ⌃P
In my case hitting ⌃P followed by hitting Return, will launch or switch to Photoshop (my default App for ⌃P).
And as the Conflict Palette is invoked by pressing ⌃P I can just click on one of the lesser used apps to launch it. A bonus is that putting a ↩ at the head of the Macro name, lists it at the top of the Conflict Palette.
Nothing to remember apart from the first letter of the App name and which one is my "default"
To achieve this, the Photoshop launching/switching Macro is set up like this:
For me its very simple (I'm a simple person unless you asked my wife)...
I assigned the same trigger (very easy to use- just cmd+option w/left hand and "o" w/right) to all my "more used" apps (which are not too many) and when the conflict palette activates I just hit the 1st letter or, if there is more than one app, the 2nd one too.
That is what I do. I emphasize that it is a lot quicker than it sounds. People avoid it I think because it sounds slow calling up two palettes, but in practice it is really just a short sequence of keys, in my case no barely slower than a simple multiple key press.
This is my preferred solution, too. Using Caps Lock has two big advantages:
You don't have to worry about overwriting existing shortcuts (e.g., there are a ton of Control-based emacs shortcuts on macOS).
Caps Lock plus one letter (ideally one on the left half of the keyboard) is easier/faster to press than a shortcut involving multiple modifier keys.
What I find incredibly useful is to have macros that don't just open apps, but work as toggles for those apps (i.e., the first time you hit the shortcut, the app is activated, and when you press the shortcut again, you switch back to the app you were in before):
So, if I, for instance, just want to quickly check something in my calendar, I hit CapsLock-C to switch to BusyCal and when I press the same shortcut again 2-3s later, I'm right back to where I was.
I started with only a handful of apps, but today, I have toggle macros for my 15 most frequently used apps, and switching apps using Alfred or Cmd-Tab feels kinda slow.
@NSSynapse Activate an app and switch back to the last app with the same shortcut is interesting. I did not know this feature. However, I find it easier to always have the same shortcut, cmd + tab.
Hyperkey: I must confess that I never really understood the fascination for it. Probably it's just a habit. Anyway, pretty much the same works with KM, e.g. with palettes. Which still has the advantage that I can see the shortcuts if I don't remember them by heart.
Almost the same setup here, except that I mapped CapsLock only to ⌘+⌥+⌃. Gives me twice as many keybindings, one for each letter when shift is pressed and another when when shift is not pressed.
If two apps start with the same letter, the more frequently used one is activated without shift, e.g. Finder is activated by ⌘⌥⌃F and Firefox is activated by ⇧⌘⌥⌃F.
Infrequently used apps are usually launched with Alfred, don't bother remembering a keyboard shortcut for them^^.
When CapsLock is pressed alone without any modifiers it is mapped to escape. Love this setup so much!
