3 I hope all goes well with your project.
希望您的项目一切顺利。
I hope all goes well with your business.
祝您生意兴隆。
Hope everything goes well with your study.

希望你生意顺利。

4 Let me know if there's anything I can do for you.
如果有我能帮上忙的地方，请尽管告诉我。
Please let me know if you need my help.
如果您需要我的帮助，请告诉我。
Good luck with the project. Let me know if I could be of help.
希望项目进展顺利。如果能帮上忙，请告诉我。