A paragraph

1. thesis/introduction (topic sentence)

2. supporting point

3. example

4. conclusion)

E.g.

You shouldn't fully trust your first visual positive impression of a person.
It is not a good idea, because first impressions can turn out to be wrong and obviously what somebody looks like does neither tell you who they really are nor how they will behave or if they are reliable.
For example a person that has just been to the hairdresser, has rented a very nice outfit, put a lot of effort into their makeup and has learned to smile amiably may be a fantastic actor or actress - but still could be the most unreliable friend, most inconstant partner or worst parent in the world.
So you simply need to be a bit more careful and allow yourself some time to find out what this person acts like if somebody asks them for help, when there is no audience, when there is no reward or when they are tired and stressed out. This will give you a true idea of their character - not heir fantastic first impression.

Starting a paragraph with a topic sentence

A standard paragraph starts with a topic sentece, which ...

is usually a rather general statement
has a direct, clear message (choose verb accordingly!)
signals the kind of paragraph that will follow (an explanation, a list of examples, a definition of the problem ...)
often asks or implies a question and promises an answer

Zum Sichtbarmachen der Lösungen einfach in der rechten Spalte mehrfach in das leere weiße Feld klicken!

Topic sentence	The reader thinks/wants to know:
I am clearly against a speed limit for several reasons!	What are these reasons?
There can only be three possible answers the British government may give.	What are these answers? Why can there only be three?
The events of last week were a terrible blow for those who love their freedom.	What happened? How is freedom endangered?
It seems unbelievable, but there is no way to save Tibet's cultural heritage.	Why not? Why is it not possible?