良い大学に入るためには、あなたは一生懸命勉強するだけでよいのです。

、。

To get into a good university, all you have to do is study hard.

Literal

Good university [in-に] enter [in-order-to-ためには], you [topic-は] one-all-[of-の] one-all hard-ly study only-だけ good.

~さえすればいい ('all you need to do is X, you just have to X') is a set minimal-condition pattern. ~ためには ('in order to') — purposive + contrastive は. 一生懸命 ('with all one's might') is a classic 四字熟語. A bit stilted as advice.