Not Pro, anyone using command-line FFMPEG and other tools can probably do much better. In fact one of them just did, by improving on my attempt at the 5min Madoka ED in the OP/ED thread.
My approach is generally this:>Resolution
30s or less? 720p
Is it long (1min+) or busy with lots of movement? 360p
Encode with 40 CRF, 2 tolerance and audio quality 0 (never found much need to go higher on audio unless its an old Mono show like DragonBall)
Based on the filesize of the result I either drop the resolution (720 -> 480, 480 -> 360 and 360 -> 270) or move to the next stage. Usually I only drop res if the output is 5MB or higher and I can't see any reasonable trimming options.>CRF and Tolerance
Next I start dropping the CRF until I find the lowest number that leaves a sub-4MB output
Shows differ in their ouput but I tend to see 40 as highest before it looks shit, 30 good and 20 best.
If you are hitting 20's you could try upping the res a bit
I see no reason to ever go below 20 CRF, the difference in quality isn't discernible to my shitty eyes
Finally once you hit your CRF floor, start upping your tolerance until you hit below 4MB
I see no point to ever go above 10 Tolerance>FPS
I've only recently started playing with the Frame Rate option in the advanced tab.
Testing seems to indicate that from a source 24fps vid you can usually drop to 20fps, sometimes even 18fps before it becomes noticeable. This gives you a bit more room to play with to increase your CRF or even your resolution. it helps massively on snowy/static scenes where bitrate usually skyrockets>Subs
Sometimes removing subtitles can help, especially on those annoying scenes where a sub from the previous frame is still lingering or on shows like Hataraku Saibou where the subgroup throws a wall of text on the screen.
I use a tool called MKVExtractGUI that plops out a .srt file from any mkv you throw at it, then I edit it in notepad to remove lines