This is my approach, it works for me.
Everything goes in here: notes from what I read or come across, sometimes so I didn't lose track of them, course related comments I post on people's blogs too.
A good deal of this remains hidden (private), however I will sometimes 'expose' notes and cryptic thoughts in case someone can make sense of it for me, or chivvy me along to construct some rounded thoughts and sentences with the stuff.
There's some random stuff too.
Tagging matters immensely.
'Search' leaves it to chance, which might help you serendipitously to come across a thought or note you had, but is scrappy and can be time wasting, rather be tag happy and have a system.
Everything gets the module reference, if there is an activity reference this is added as a single word such as 'h807activity3.4' or some such so that it can be searched for and found with ease.
Come TMA time I revisit all the content from that block and start adding the tag, for example, 'h807tma2', or as I'm currently doing 'b822tma3'.
Gathered in one search list I then go through each relevant post refining my thinking.
At some stage I may add further tags to identify arguments or to give it a chronology if that isn't apparent. I then cut and paste to a word document.
I MAY assemble in PowerPoint simply to help shuffle ideas around.
A system?
Hardly. Each to their own. I panic like anyone else over an assignment but know the stuff is here and having done the reading and activities and having shared my thinking and had this coloured and shaped by others that I ought to be able to assemble a cogent case.
Tags are strategic, Search is more random.
I switch between the two when revisiting note