Chinese Formal Letter Writing

What's the best way to conclude formal letter writing? I'm not talking about the format but the final paragraph.

Is it 我希望.....?

if you're expecting a reply,say 希望能收到贵公司的回音。谢谢。

think so ba.long time never write in chinese alr.

Don't you have to thank the dude for reading the letter and say that you hope that he would implement your solutions?