well first of all Ladysakura,I have to say sorry for the comment I will post now,it's very direct,and it may be hurting,but it's with comments like that that we improve on photoshop..
your banner is very bad done and have a lot of errors.
first thing:the font you used...it's damn ugly,too much pixellated,a color that dont have nothing to do with the rest of the pic,and the rotation is just useless,cause we cant see very well what's written,it's not something we can just stick on a website banner ,not mention that you didnt use any shadow or external light effect,wich would have been better
second thing:the characters are placed a bit too much randomly,it's somehow okay with sakura and misuzu but the sailor moon girl and kero dosent have anything to do here ,also the shadow effect is way too hard,you should have
reduced the opacity of the shadow and also added an exterenal border or external light,it's the most important thing when sticking characters in a white background
and finally:the background,well,I dont have anything to say here,it's just that the colors dont go well with sakura and it's a bit sad cause it's kinda cute with misuzu
and that's all,I hope you will not hate me for saying such things,but trust me ,it's some absolutly killing comments like that from friends of mine on my first works that gave me the will to learn more and more to try and master photoshop , and sorry ^^
as for the banner,I dont personally have the time this days but I will try and make something too ,wait and see ^^