Draft your text, then go through it ruthlessly eliminating unnecessary words. You are increasing clarity and cutting costs.
Don't make your details too complicated: if the time and price change every day, don't confuse people by including all the details - instead, tell them briefly where to find the full information.
Keep as near to one idea as you can get. Decide on your marketing strategy and reinforce it - as often as possible.
It takes a long time to change people's minds.
For practical purposes, you can only release desires already there. So don't advertise unless you are giving understandable information rather than trying to convert people.
First impressions: aim the first words at your target audience.
Start your classical concert ad with 'Puccini...' and those who care about Puccini will read the rest. Nothing can be done for or with those who think he was some form of Italian ice-cream.
Not everyone knows what you know!
You may work in the JR or the JDP, but the Philosophy student coming to your Marxist meeting there hasn't a clue where it is. Always assume that no one else knows anything and list your venue's full name and address. If you want to use a link to the venue's website instead, make sure the contact information is prominent and up to date before placing your ad.
Size: it can matter!
If you can, be larger than your competitors: it's easier to get someone's attention with a larger advert. If designing your advert yourself, make sure the most important words are very large and very bold. If people are attracted by the headline, they'll bother to read the rest of the text.
Repetition, however, is possibly even more important than size. Reinforcement works. This is especially true if you're advertising a service: your advert may need to appear a few times before people get around to sending that email or making that phone call. There is no doubt whatsoever that no matter what it is, your enterprise appears less important to everyone else than it does to you. Imagine trying to interest a deaf tortoise, and you've about grasped the measure of clarity and repetition required.
What's special about what you're selling?
What have you got that the others haven't? This is known as your Unique Selling Point (USP): make the most of it to hive off a market with a special appeal e.g. "The Only Musical in Oxford This Term". Make sure it does have a special appeal though. "The Only Musical in Oxford with a 2nd Trombone" won't do (they won't recognise it as The Mikado).
Be consistent: got a company logo? Put it in your ad.
Advertising Budget: a minimum of 10% potential turnover is recommended. There's no point investing in period wigs, authentic props and rehearsal space if no-one knows about your show!
if possible, include a web address. If people can go easily and directly to your site for full info, they will. They may trust you more too; a good website shows that you have invested in making info about yourself public, and may be more serious than the service provider who only includes a phone number.
The truly tech-savvy can now use a QR Code in their print advert too. Viewers scan with their smartphone to go straight to a website). If you wish for immediacy, include a phone number in your advert. If you prefer to handle reponses at your own pace, just include an email address. If you have the budget and want to cover all bases, include all three(/four)!
For small private ads, we find the the greatest response from individuals goes to e-mail addresses, then phone numbers, then postal addresses, then box numbers.
When you feel you've finished your advert, get a disinterested party to look at it. What do they think you've said? Their answer will tell you if you've made a good advert, or if you need to make more changes.