Hello,
next week, I will appear ZD exam. I need your support for the follwing Brief writing:
1)letter: One of your friend want to visit you, tell him where to visit, he likes sport, advise him which sport club he should join.
2)letter: Your friend dont take interst in his study and has problem with his parent, advise him how to get out this situation and tipp for finding job
3) Your brother is always watching TV and all the time in home--> how to get out this situation.

thanks in advanced for your help.

It is very likely that the actual Brief which you will have to write in ZD is on none of the above topics.

So my suggestion is to practice writing some briefs and learn the following points:
- Start & end of a informal and formal brief
- Arranging the points to be included in the brief in the right order
- Make sure to write 1 or more sentence on each of those points.

Wish you best of luck. I took a Vorbereitung (preperation) course for giving ZD at VHS and this course really really really helped me and I highly recommend it.