My first submission in something like this, so any constructive words would be very useful :)
Fonts- minimal, sans-serif fonts for a kind of classy contemporary look.
Background- blurry, abstracted lights to add some vibrancy and the feel of a late-night bar/lounge/party atmosphere.
Misc- added some descriptive phrases so it'd sound more enticing for people to attend the launch party, and I figured an address is usually part of an invite so I made one up!
Also made the invite double-sided with the front being simpler (with just the essential info) and the back a little more detailed (more descriptions, voucher on bottom).