When I first started my genealogy research - really started it, as in got a software program, joined Ancestry.com, etc. - I was so excited just to plow right in and start adding as much as I could to my family tree! Pretty soon I had dozens of limbs and branches, covered with little shaking leaves... you know the excitement, don't you?
I added and added and added. Wow! My father's line went directly back to Sir Thomas More! My mother is a direct descendant of the bastard brother of William the Conquerer! Amazing stuff!
The problem with all that amazing stuff is that so much of it was wrong. Wrong or unprovable. I knew so little about what I was doing that I started out by accepting every Ancestry "hint" and taking other people's undocumented word for things.
Sadly, after a year or more of this jubilantly adding generation after generation to my tree, I found myself having to become a careful tree surgeon - pruning incorrect people off it one by one by one. On Ancestry and many software programs you can't just lop off one branch of a family tree, you have to take it off person by person. And when you have added hundreds of people incorrectly (or accidentally added dozens of duplicates, as I had also done) it takes a long time to get your tree straightened out.
So if you are just starting out, take my advice. It's thrilling to find more and more info about your family, but slow down, and learn as much as you can about what you're doing as you do it. Learn about how to avoid adding duplicates to your tree. Learn about how to judge whether or not the "hint" you're being shown is a valid one. Don't just add people willy-nilly to your tree. Believe me, further down the line, when you've got several thousand people on your tree, but you are reasonably certain that they all actually belong there because you've done your homework, you will thank me!
Next time: How to learn about genealogy research - for free! You don't have to pay for your genealogy education, and I'll show you lots of resources to get you started!