Ok my favourite footballer is Ergün. You know he plays for Gs. I think he is the most powerful player in the team.
Also you should write " sergen is an important footballer", not "sergen is important footballer". I think you should be more careful on article usage.
Another mistake of yours is that you wrote " my favourite is hakan" you should write " my favourite footballer is hakan" or "my favourite one is hakan" (benim favorim olarak düşündüğünü sanıyorum, fakat ingilizcede favori sıfattır ve bir ismi nitelemelidir)
now the question for the one who is my below: How do you feel when you meet someone for the firs time?
Not: bazı açıklamaları türkçe yapıyorum ki kolay anlaşılabilsin. Böylece diğer arkadaşlarda bu hataları tekrarlamazlar.