Do you use a control surface fader?
Do you use a knob on a midi keyboard?
Do you ride a fader in your DAW?
Do you use scribble it in with your pencil tool?
Do you use a Midi foot controller? (I do lol).
Does everyone understand the difference between automation modes? Read/Touch/Latch/Write/Touch-Latch?
Bought myself a Behringer BCF2000 controller - best thing I ever did! It’s a little on noisy side with the motorised faders, but I can really get automation dialled in.
I also got a second hand Korg Nano controller, and I’ve programmed that to control certain MIDI CC commands, so I can play and control parameters live.
I built myself a MIDI foot controller, solely for the purpose of having a wah wah pedal for my virtual amps. I built it from a cheap expression pedal and a Teensy board. The whole thing took me an hour to make.
I will quite happily edit automation moves with my mouse. Sometimes I will take my fader rides and then tidy them up with the mouse. I find the faders will dump hundreds of separate fader points on my automation graphs, so I’ll go in with a mouse and just make those changes smooth.
And no, I don’t understand all the modes! I keep all channels on Read, until I need to automate at which point I switch to Latch. I find in Logic that putting it on Write just causes me too much hassle and makes my playback stutter. What are the differences?
lol. That used to drive me nuts. Then I realized it was normal 
Here’s the cleanest simplest description I can find…copy based from the avid website:
Auto off- This mode will bypass all automation written to the track
Auto touch-This mode will duplicate all curves you created, until you touch the fader. One you touch the fader, new automation will be written for the duration of the time you have your finger on the fader. Once you release the fader, the automation will revert to pervious written automation curves.
Auto latch- This mode behaves just like auto touch but, instead of moving to the previous automation curve when you release the fader, it will stay where you last left it “latching” to the volume level.
Auto write- This mode is an “absolute write” mode: it records the position of all write-enabled controllers from the time that playback starts, to when it stops. It erases any previously recorded automation on the track for the duration of the automation pass. When you stop ProTools while you are still “holding” a fader or controller, ProTools will ramp up or down to the next automation position on the track. Write mode is most useful for recording a first automation pass. Once you have created this basic first pass, you can edit or augment it by recording additional passes using Touch mode.
Auto read- This mode will simply play Automation back that was recorded to the track.
Trim Automation- This mode will maintain your automation curves that you created and raise or lower the volume as you see fit. Actually really handy when you hear the sentence “That automation curve is great, but can you bring it down just a hair…” This mode is much less time comsuming than redrawing the entire automation curve.
A good workaround to this situation is to send the automated track out a bus, and then re-record to a new track. From there you can boost or attenuate the volume accordingly. You will not be able to edit the origianal automation curve, but you will maintain the volume changes you wanted.
I tend to pencil automation in personally
I ride the faders/controls in my DAW then clean them up with the mouse. My family got me a Novation Launchkey Mini for Father’s Day last year so I can do simple pads and whatnot. But whenever I try to sit down and try to get the buttons and knobs to work with Studio One, I get impatient and move on to something more fun. A Faderport is on my list, but then I look at the Launchkey Mini and kind of wonder why…
I do it all by mouse in the DAW, adding points where I need them and adjusting them manually. It’s a lot of work doing it that way but it’s the only way I know how, not having any other hardware but a computer. I tend to try to get the levels balanced to the max extent possible with the DAW’s mixer faders, then compressing, limiting etc and do automation only as the last resort to deal with those things I can’t balance any other way.
And of course, just about every quantity in every plugin can be automated, not just level. I use those functions a LOT, changing amp sim settings or compressor values, tweak the rotary on/off on a B3 track, or what have you.
I had not heard of those different modes either… in Mixcraft, you just put every automation point you create at whatever level you want, and it stays there. One adds as many as one needs and adjusts them as required. The “baseline” level stays at unity/default until and unless you mod it with an auto point.
I too do it all by mouse - I have thought of getting a control surface - but with ProTools you can only use the HUI or Mackie protocol, which limits actions and features on 3rd party products - unless you buy the prohibitively expensive Avid surfaces… so my mouse works fine for now!!
I dial in my automation with a mouse in Reaper. I usually have to do a few takes before I get the automation to my liking, but it’s easy to do and I’m happy with it.
The different mode’s in Reaper’s automation are
Trim/ Read
Read
Touch
Latch
Latch/ Preview
Write
and anything can be automated. You can even automate every frequency band, Q, level, etc., in your 20 band eq if you want. It’s probably the same in most DAWs. I usually just use the volume automation and lately I’ve only been using the Trim/ Read mode because I forgot how to use the other modes, haha. 
I learned all that stuff in Pro Tools certification years ago, made perfect sense and did the exercises to make it happen. I tended to do the pencil automation out of expediency, but was challenged in another class at one point to actually use that knowledge and do live automation on multiple tracks using faders and knobs. It was awesome to learn that! But it took a lot of energy too, like when I read about CLA and others running live automation on a console.
One concept I learned, at least in Pro Tools, was to update a stereo mix in “real time” with automation on the individual tracks. In other words, the stereo mix had already been bounced to another track, and with automation and output to the stereo mix track you would actually over-write portions of the stereo final mix! This was done section by section of the song, and really worked quite well, though it took intense concentration to all the details. It could be done on one track at a time, or multiple ones, whatever you thought you could handle. And the instructor worked in Nashville at the time and said that was how those guys did it all the time! They were on timelines and deadlines and focused on “just getting it done”. It’s amazing how that mindset can focus you on workflow. 
It’s something I haven’t aspired to in Reaper, though it may be quite possible. Having a controller could make it so much easier. First step is knowing how all those modes work, so your thread is awesome Jonathan! Second step is actually trying it in a mix, and believe me it’s scary to take that risk in a sense, but you can always hit Undo if you f*ck something up. And you can always “clean up” with pencil automation what didn’t quite work at first “on the fly”. It’s all choices, just do what works best for you in the situation.
That said, there are tons of plugin parameters that can be automated to the point of insanity, so choose your battles. Volume and panning are obvious ones, but one trick is the sliding EQ frequency HP or LP that can be easily done with either method. It sounds pretty slick. Also, the Bypass On/Off for the effect which can be essential in certain circumstances. Or Bandpass On/Off which can give you the “Aqualung” or “AM radio” type effect.
That’s also commonplace in film where you get asked for a tweak and you overwrite a portion of the surround sound stem because re-rendering an entire movie just to bump one actor up 2.5db for one line would be an insane waste of money. So you re-print a portion of the stem then surgically re-insert the re-printed stem back into the final dub mix.
I’ve not done it personally in Cubase yet but I’ve seen it done this way so if I ever get really serious, this is probably how I’ll do it.
I pencil it in also. Very personally.
I use a combination of the pencil tool and using touch with the trackpad to drag like a fader.
Now there’s a song title waiting to happen…