If you are good at copywriting, you should be able to translate that general skill over to the writing of PPC ads. I would recommend reading Gary Halbert's material to start.

[DELETED]

Always test, never guess what you think will work and what will not work, it often will be a surprise and or opposite.

follow your ABC's

A = Attention (line 1)
B = Benefit ( with feeling ) (Line 2)
C = Call to Action (Line 3)
D = Desirable Destination (Line 4)
-
E = Make it exiting ( not drab n boring )
F = Full house / where possible use all available chars

put youself in the shoe of the customer, try to think about what important feature they would look for in the product or service. create a short but catchy tagline around the strength of the product/service. try several varations and see which ones pull the most clicks/sales

Check the keywords you looking for and people competing up to it.

Read their ads and find out what how they hitting on the keyword. DON'T COPY THEIR AD.

It will help you coming up with yours.