How to be become better friends then u aldready r?

I have a best friend and were friends with this other grouP of ppl but they r more " popular" i think then me and my bestie and were not the bestes friends in the whole invite world but were best friends. Now, my other friend is kindof excluded like me and my bestie , she said that maybe I should invite the " populaire" group to my bday party cause we don't hang alot but I had no IDEA WTF she was talking about cause we hang lots ( but the " popular" group isn't in my cl which sucks) but we hang allll the time at lunch and "recess" so now I'm very confused and need help pleaseeeeeeeee help me I'm desperate my party is commit soooooooooon!!!!!!!! THANKS