Winnie the Pooh is one of the most popular and famous [you could also use: well-known] Walt Disney's cartoon character [here, you need plural noun form, CHARACTERS]. This [THE] bear is Christopher Robin’s best friend and lots of children's friend. He is also my favourite hero from animated fairy tale [FAVOURITE FAIRY TALE HERO; by the way, why do you think that Winnie the Pooh is a MALE character? ;p].
The Pooh is the [A] fictional [it doesn’t fit here] yellow bear that wears [also: WEARING] a red T-shirt. He is plump and fluffy [we use adjective ‘fluffy’ to describe things such as towels or toy animals, not people]. His disarming smile can cheer everyone up. Similarly [what did you mean?], Pooh has got small, black eyes as coal arise liking [it is incorrect, I am afraid]. His facial impression [verb confusion] express [it does] what the bear is feeling and thinking. Also his plump body is very nice [wrong word order and word confusion, HIS PLUMP BODY IS VERY NICE, TOO]. His uncoordinated movement and amusing walk [maybe: WAY OF WALKING] are unique [THE ONLY ONES OF THEIR KINDS could be also used].
Pooh is known as the bear of very little brain. But he is a bear with a big intelligence. He is charming and pleasant. This is a friendly and likeable character, which has lots of friends such as Piglet, Trigger and Rabbit [I’m not sure whether we should use the indefinite article with all these names]. He is popular because his manners are natural and reliable. Pooh is absent-minded but cuddly [NOT ONLY IS HE ABSENT-MINDED BUT ALSO CUDDLY]. His advantages predominate over his faults [‘to predominate’ is very formal and it doesn’t fit here].
He loves to sit [SITTING] under a tree and think [THINKING] [HE USUALLY SITS…]. Under the tree called Mr. Sander he thinks about what he should do [SITTING UNDER THE TREE CALLED MR (with no full stop) SANDER, HE THINKS WHAT HE SHOULD DO]. Usually this [IT] means thinking about a time for honey [THINKING OF HONEY]. His biggest worry is honey [with no comma] because he eats honey at breakfast, lunch and dinner and always he has not enough [it makes no sense]. As a result, [comma] many adventures with Pooh are about [ARE CONNECTED WITH] honey. But Winnie's favourite occupation [word confusion], [comma] except [EXCEPT FOR] eating honey, [comma] is helping others. He very often wants to bring help [TO HELP] his friends when they are in trouble. Not always it is [you should have used inversion, NOT ALWAYS IS IT] a success, but he has very big heart for them [is ‘to have big heart (for)’ really in use?].
To sum up [also: summing up] I would say that there is something special in this optimistic, stuffed [;p] bear - it is something from a child [CHILDISH?] what causes a smile. And this is the main reason why I like watch [love / like / enjoy etc. + -ing form, LOVE WATCHING] all cartoons in which Winnie the Pooh appears [I am not sure whether it is correct; maybe: WHICH HE APPEARS IN?].
Nie wiem czy to wszystko, nie wiem czy czegoś nie przeoczyłem, nie wiem czy nie palnąłem jakiejś gafy, nie wiem, nic nie wiem! Tak więc, najlepiej byłoby, gdyby jeszcze ktoś na to rzucił okiem, skoro już tak sie tego rzucania przyczepiliśmy. ;)