First of all, use your own influence. Of course, do not just say directly that terrible and that's fine, but right step will comment on the fact that you like, and what is not. Make comments in an unobtrusive, playful form, however it was strange, it is a form of criticism to the men most sensitive.
Take part in a joint campaign to the store and sorting already available items. Advise him that he goes and what does not, and houses have shifted away those things that you think he did not go.
Get subtlety in influencing his taste in clothes. If you overdo it with the impact of the result will be the opposite of what you want.
Play on his feelings - stand with him in the mirror and tell him how you look next to him. Try to pick his outfit together, based on how you feel. The most important thing is that if you take into their own hands influence on him, in any case should not go too far, otherwise you do not get affected by it at all.
Remember that men like small children - good for them to be encouraged and for bad - to scold. Likewise here - praise it the right choice in clothes and just keep silent, when suddenly it turns out that it puts in the wrong direction. As already mentioned, the main thing - that he did not feel the pressure.