If you had any idea just how vastly different the comic and show are, you wouldn't have a problem knowing everything that happens in the comics. Go Read A Fucking Book!
Sofia & Andrea never died in the comics, Tyresse had his head hacked off by the Governor, not Hershel, Shane died before they left the camp, and was killed by Carl, Tyresse was introduced before they arrived at Hershel's farm, Dale should still be alive, Allen, his wife Donna, and twins Billy & Ben(Billy was never even introduced in the show) were at the camp site when you first meet them, Megan was Lily's best friend, who the governor rapes before she kills herself, not Lily's daughter, Bob Stookey is a white 'nam vet, following the attack on the prison the group(minus Rick, Carl, & Michonne) wind up back at Hershel's farm, where they all meet Abraham and co., Judy & Lori were killed by the same bullet, Lily fired, she then kills The Governor for making her kill a baby, before running into the prison for some remote protection.
That's all the changes I can think of off the top of my head, and not involving characters that were not in the comics.