All but one of the schools I applied to transfer to required applicants finish the first year before applying. All but one of them did not even accept transfer apps until something like May or June. There was one, I believe, that would "conditionally" accept a transfer after the first semester, but I think that school still required applicants complete the first year before the transfer.
Grade-wise, I did really well my first semester, and then slipped a bit second semester. I didn't have any trouble getting into the schools I applied to transfer to, but then I didn't apply to transfer to any of the so-called top ten.