I have a calendar on my bedroom door, a calendar on my mobile phone (which I don't use much because the alarm never sounds!) and I place post-it-notes everywhere. I find that I like the post-it-notes best because they're colourful, eye-catching and can be placed wherever you need them.
I use the reminder for everything.... if the data and date I need is not in the mobile than It doesnt exist. Hell I even use the clock alarm when Im cookiing... if the recipe says 15 minutes, I put it on and set the timer to remind me.
I put on the memo program all my grocery shopping items I need to buy.... and delete them from the mobile in the shop as I load that item into the cart. I save Birthdays, Doctor appointments, Social engagements, reoccurring requirements for my dog's well-being (like worming, flea medicine) and bills are due.
Like I said.... if its not listed in my phone than it doesnt exist.