No spam emails to the clients?

Hey guys. For a while now i am confronting this issue- We both know that when you got a new website, there's also webmail available. Now, the issue is, when i send an email to my client(s), they receive it in the "spam" folder which is not exactly favourable to my business.
Is there a way to stop this? To make sure that the emails go directly as "no-spam" ?

Cmon peeps need a hand!