I've been keeping a good things jar since 2012 (which SOMEHOW was 5 whole years ago already!) and it's one of my favorite traditions. If you're not familiar with the concept, you just find a jar (or bowl or cookie jar, whatever) and throughout the year, whenever something good happens, you scribble it down and put it in the jar. On New Year's Eve you open it up and read through all of the good things that happened that year!
My 2016 jar was busting at the seams (the lid wouldn't even stay on, it was so full!) Of course I include the big things, like Paris and Rome and seeing The Killers in concert, but my favorite ones to read on NYE are the smaller day-to-day things that you might forget by the end of the year. My mom made me soup when I wasn't feeling well. I got ice cream with my dad in the summer. I helped my brother fix up the backyard before a cookout. I spent a night binge-watching tv with one of my friends. I also include inside jokes which, by the end of the year, usually make NO sense. I wrote down that me and my mom went "galavanting to find feminine needs" I HAVE NO IDEA WHAT THAT MEANS NOW. I also write down funny stories, like the things that cause side-splitting bursts of laughter (which inevitably seem less funny than the laugh attack at years end, lol!)
I also throw in mementos like ticket stubs, wristbands from concerts, metro cards, and a seashell from each visit to the beach (I write down the date with sharpie on the back of the shell before I add it to the jar!) In January I collect up all the good things and put them in an album along with corresponding photos from the previous year. It might seem hard to remember to write things down at first, but it really becomes second nature as time goes on. I'm so glad I stuck with it, because once I wrap up my 2016 album I'm going to have five whole years worth of scrapbooks filled with good things and happy memories :)