when I started out doing colour developing (c41 and e6) I bought a box of 10 of
these - they hold just a smidge over 1 litre (to allow for frothing of liquids when pouring back), and flexible enough to handle being squeezed to expel air after the bubbles burst. Plus, they aren't going to be mistaken for anything else. I've also used the spares for my made-up b&W chem's .
Blue tape on the lid and around the bottom of the Dev, Red on the Stop, Yellow on Fix, Green on BLIX, Black on STAB. - and C41 or E6 in indelible black marker, No tape and it's a stock bottle so is marked with contents ID-11/Perceptol etc. I also use the tape to colour code the bunch of measuring jugs (50p each from asda) in the same way. Sad obsessive git that I am, I've also made up a form on the computer with process routines for E6, C41 or B&W, which again have colour bars at the side of the stage. Did I mention i'm a sad obsessive git? Yep, good
Ring binder in the processing kit box, each sheet in order, so I can see how long I souped the last colour film for, and how it came out - so I can adjust accordingly - both for depletion and other anomalies. It's all about establishing a routine and being methodical. Or a sad and obsessive git