What else can I write about an advertisement? It persuades viewers to not smoke, and shows a bloody hand holding a cigarette.

Without knowing exactly what anti-smoking
commercial/advertisement you are discussing, I will encourage you to analyze the
persuasive techniques used and how effective they
are.

There are common techniques used in advertising (both
print, audio, and film/TV) which you should look for in the example you must analyze. 
Use the list below:

1. Bandwagon: "everyone" is
   using (or not using) the product


2. Celebrity endorsement:
   is someone famous featured?  Consider in audio, is a famous voice
   used?


3. Emotional appeal or transference: the ad is
   designed to trigger a specific emotion which the audience may then transfer to the
   product.  (In this case, perhaps the emotional appeal is fear.  The ad is somewhat scary
   making the audience believe cigarettes are somewhat
   scary.)


4. Humor


5. Plain/average
   people: appeals to the everyday/common
   person.


6. Individuality/anti-bandwagon: sends the message
   that not everyone is doing it, therefore by doing it you will be
   unique.


7. Slogan: a catchy saying that sticks with the
   audience


8. Loaded words: uses words with very obvious
   positive or negative connotations


9. Product comparison:
   stacks one product against another to show obvious advantages over
   disadvantages

You could include one or more of
the above techniques in writing your advertisement analysis, and show whether they are
effective.