The end of a year is always a good time to harvest interesting designs from old calendars. The calendars can't be used again and will obviously end up in the trash, so before they go, quickly flip through them to see if there are any designs worth cutting out and saving for projects such as personalising homemade cards, or decorating containers. Ideally, the paper should not be too thick as that would make it difficult to stick on, but otherwise just about any type of paper would do.
Before starting on the project, it's a good idea to go through your stock of paper cutouts to choose a few that seem suitable. From these, create a rough layout on the card itself using the cutouts, before using any kind of adhesive. This is so you can rearrange the pieces if you like, before they are stuck on.
Latest homemade card project, below. The card itself is a blank card bought at at a stationery shop, which comes with its own plain envelope. I used paper cutouts to create a personalised design on the front.