You can also use these idioms, depending on the situations, 近水樓台先得月 不入虎穴焉得虎子, 只要功夫深, 鐵杵磨成針

your are the best.你是最棒的！ you can do it.你可以做到的。

To express support can use "加油“”，“”支持“”，“”挺你"，but except"加油"can use in individual，others should relate the contexts.To express sympathy can use "可惜"，”可怜”，but still needs to relate contexts, because they can be used in other express.

我支持你。I agree with you. 我是站在你这边的。I stand by your side. 努力！is similar to 加油 I can think of these so far. If you can provide more contexts, maybe I can think of more expressions for you.:)

if you want to cheer a friend up, u can say 别不开心嘛！don‘t be sad 想开点think on the bright side! 多往好处想think on the bright side! 坚强点！be strong! 别气馁！Don't be discouraged!