I used 'Baby Log' - it logs breastfeeding, nappies and sleep - all with a timer so just keep it close by and at the end of the day you have a consolidated chart of everything they have been up to during the day. Total sleeps, nappy changes and feeding as a summary. I used it for the first few weeks when I constantly needed reminding of what was going on and it helped to figure out patterns of his natural behaviour so I could start working in a routine alongside him.
I also like looking back on it now to remind me of how much progress he has made.
Obviously a pen and paper work just as well! But no graphs!