All of your hard work and dedication has molded you into an amazing young lady.
or
All of your hard work and dedication have molded you into an amazing young lady.
"have"
plural subject ... do you see that?
http://www.quickanddirtytips.com/education/grammar/compound-subjects
Hard work + dedication to me is a single subject, not compound.
All of your hard work and dedication has ..
Now if it had been
hard work and luck I would have went with compound subj.
Disclamer: I hated my 9th grade Grammar teacher, and it was certainly likewise.... I shut out a lot of lessons I should have mastered.
Well, Writeacher and I disagreed, but in general, you would be wise to trust Writeacher in these matters.
Well, actually, the subject is "All"
http://grammar.ccc.commnet.edu/grammar/pronouns1.htm#indefinite
Is "All" singular or plural?
I'd decided that it was plural since "all" referred to two things -- hard work and dedication. But I backed off for the reasons that Bobpursley gave.
http://englishplus.com/grammar/00000027.htm
I disagree ... I see "hard work" and "dedication" as two different things.
It'll be up to Suzanne to decide!! =)