I think that wearing school uniforms have {HAS} many advantageS and disadvantageS.
Started to {STARTING WITH THE} disadvantageS{,} Firstyly{first of all}, every girl and every boy are wearing {PRESENT SIMPLE?}the some clothes. This is very boring. When we are going{PRESENT SIMPLE?} (for school passage{THROUGH THE SCHOOL CORRIDORS}, we can see only dark colours and nobody {bez:don't, lepiej: IS/LOOKS} diffrent.{pis. DIFFERENT}(?)
Secondly, the school uniforms are uncomfortable and we are feeling{PRESENT SIMPLE?} bad. Next{,} our mums must washing {WASH!} uniforms everyday, becouse{pis. BECAUSE} it's not healthy. We are limit of free styles{co masz na mysli? WE HAVE A LIMITED FREEDOM OF STYLE?}, too.
Now, some advantages. {to nie jest pelne zdanie}
All students wear the same uniforms{,} so{bez przecinka} we are egual{pis. EQUAL}. The uniforms are cheap and we are {lepiej: WE LOOK} elegant, too. We aren't wearing{PRESENT SIMPLE?} mini skirts or dressES. Also, when we get up in the morning{,} we don't {HAVE TO} thing{THINK} about to wear.
I know that people from the older generation think that the school uniform is {A} good idea, but that opinion is not shared by my peers. {sama pisalas to zdanie?? ;-)