A few thoughts before thinking about your 30 second promo script:
What's the message?
30 second videos should be a statement piece. It's easy to want to add more information in each 30 second video but you risk your message becoming diluted. Focus on one message and direct your efforts in supporting that message.
Who are you targeting?
Think of your target audience as a very specific person who is looking for your product or service. The more specific you can get, the better. If you throw a wide blanket and say "it's for everyone" then it's for no-one. If you have more than one "target person" then you need to make another promotional video that targets them specifically.
Who is most likely to use your product/service? As you answer this question, consider factors like age, buying power, location, and income. Take, for instance, a young adult who has just started their first job. They will have needs that differ from those of a retiree. They still may need your product/service but their reasons for requiring it are different. Be as specific as possible when defining your target audience.
Tie them together
How do you get your target audience to listen to your message? This is the gold! Your target audience needs to hear that your message is relevant to them. Describe the people you're targeting in your message.
Call to ACTION
This might seem obvious, but you'll be surprised how many people leave this out (in videos and websites). What the heck do you want your audience to do?
Make it easy and if you can, give them a reason to do it right away. You may want to have an expiration date or have limited slots available, so it makes people act quickly.
Now for the boring but helpful stuff
- 30 seconds roughly translates to 75 words (average pace 2.5 words per second).
- We will need some time to get B-Roll footage. This will usually consist of location, action or doing something, talking to an audience, you being you.