Keep ad design simple, but make it snappy. Make colors pop while still being attractive. If you use an image, just use one.
Use Mandarin Chinese / Tamil / Malay language with English .
Do not put email on the text.
Large headlines are fine, but don’t make your ad so crowded it looks unprofessional. So-called “white space” can be powerful, too.
Point options available.
Have plenty of contrast between your background and the type in headlines.
Point everything you can.
Avoid all caps letter.
Avoid reversing letters out of a background
Have a powerful, attention-getting headline.
Keep text minimal; the fewer words, the better. Think more in terms of a billboard than a magazine ad.
Keep the overall design attractive, including the selection of typeface and placement of the text. I think people are more likely to click on and feel favorably disposed to attractive ads and the companies that create them.