What kind of family tree do you want to create? Do you want to scrap your own the hardway using glue, paper and other design elements? Or do you want to create one on the computer and just print it out? Or the easiest way of all, order a design online and just use your own photos to finish it up.
You could also print different things and create a scrapbook type family tree that you can piece together. Or, you could create a printable in a program and fill it in after printing it. There are many different ways of creating a family tree design, which route you want to take, will determine the entire outcome.
Some items you may need include the background, photo borders, tags, and anything else you want to use. You can collect all of these and place them in one folder. That way you can print it all and not forget anything.
If you are going to create a digital family tree, you will need to get the graphics you want to use, get your background if you want to use a background, and so on. So, you really need to get organized and think it through before beginning. That will save you a lot of time.