Landing page review - would love to hear your feedback

I know this wasn't the page you wanted us to look at, but for your main landing page I would recommend changing:

With Novocall, never miss a sales call lead ever again.
to
Never miss a sales call lead again

All the extra words in there are removing clarity from your unique value proposition: that I'll never miss a sales call lead again.

As far as the guest post page, it looks good overall. I might change the tone to be more excitable and personable "Get your post on our blog! Here's how you do it:" but that's just me. Best of luck!

Not bad at all for a WP site!

I'd gradient the header to match the subs and (possibly) lose the popover at the bottom (it seems a little too much like an ad and breaks up the flow while I'm reading).

Good job!