Here are a few principles to effective copywriting:

• Keep the vocabulary very simple;
• Show lots of personality;
• Keep it relatable/conversational - not salesy;

Here is my favorite example:

Mailchimp

The value proposition is in a big font size, it's simple to understand and tells you what to expect (easy email newsletters).

The social proof is the first thing you see afterwards and it isn't threatening or salesy - it states you can join them.

Finally, the main Call To Action is abrasive, but if you aren't ready, Mailchimp seems to have a human element by the way the link below says "Need Convincing?".