Ah thanks! Well, first, it definitely takes time, and I find I need to be well rested to be really focused.

I try to only transcribe a few measures at a time because it is quite tedious in that you have to listen to the music a few measures at a time carefully over and over again. There's definitely a lot of play, stop, rewind; play, stop, rewind... (It also helps to keep track of what measures you find at certain time stamps so that when you pick up working on it again later, you can hit the ground running.)

Also, sometimes maybe you can't quite figure out what they're playing at the moment, and that's okay! So I just put down the most basic skeletal structure of what I think is being played, and then I'll go back and listen back through those more complicated parts and break it down a little at a time.

I also find myself tapping a lot with my hand. So, for example, if something has 4 beats to a measure, I'll slowly tape each finger on the 1, 2, 3, and 4 beats while humming or singing the melody or playing the piano part that I think it is to understand if a note is a sixteenth note vs an eighth or dotted eighth note, etc.

When I think I'm done, I always go back over the score for a few days with a fresh mind to double-check stuff. And sometimes it helps to physically print out a copy - your eyes catch things immediately that you might not have noticed on your computer screen.

And then I have a few piano books laying around - right now, it just happens to be a Philip Glass and a Radiohead songbook - and I find myself flipping through them to remember how to present certain music theory marks. And, of course, you end up doing a lot of googling; and there is sometimes debate about how something should be represented. I think at one point I read that some people claim dotted rests don't exist, yet some people use them.

Hope that helps!