I'm not 100% finished, but I have the majority done. Some of Matt's are going to be store bought "funny" cards, and I haven't bought those yet.
Here's what I think will work best for me and my organizational personality.
An accordion file folder labeled "blank" and Jan-Dec.
In the front I have one sheet of paper (printed up in word without anything fancy) that has all of the birthdays and events.
In the blank slot I have thank you cards and unclaimed birthday cards (in envelopes) so I can easily grab and send them if something arises.
In each month slot I have a card inside an unsealed, addressed, and soon to be stamped envelope for anyone with a birthday I chose to send a card to (mainly brothers and sisters and parents with a few in-laws and nephews on Matt's side...my side there are just too many people to send a card for every birthday!).
Then on google calendar I typed in each birthday and set it to send me an email the week before the birthday so I remember to drop it in the mail so they get it on time.
Hopefully I can get my Christmas cards made early in the year too and add it to this. I'm just all papered out to do it right now.
About 2 years ago I went through a paper crafting phase and bought quite a few double sided cardstock sheets on sale. Shortly after I bought them I switched to fabric and haven't done anything paper since!! I tried to keep them all simple with similar elements so I didn't have to think too much. But because I was using up what I had, they don't all match exactly. Here are a few of the cards I made. (inside the bird one it says "happy bird-day")