Editing registration page/stop emails from going into junk?

[shibby2]

Hi, it seems lately that a lot of of new members signing up on my forums don't get the activation email at all, and if they do, it's in their spam folder. I've been running forums for 16 years, and it's never been like this. I must get at least 20 emails per week from new members asking why they can't post (never activated their account because they never received/can't find the welcome email).

1) Is there a reason why the welcome emails might be automatically sent to junk folders? I'm not big on how email systems work, etc, so I really don't know much about it. Is there anything I can do to fix this?

2) Where/how can I edit the registration page to give more clear directions on how to find the welcome email? Like increasing font sizes/ colors, and adding my own text too.

Any help is really appreciated, I feel like I might be losing a lot of potential members!