would i say: this would greatly contribute to successful customer advices on footwear.

or

this would greatly contribute to successful advices to customers on footwear.

thanx =)

Neither!

This would contribute greatly to successful customer advice about footwear.
(but I really don't like that much either)

This would contribute greatly to successful advice about footwear for customers.
Make sure it's ABSOLUTELY CLEAR what "This" is referring to.

NOTE: "advice" (there is no plural form of this word)

thank you ;)

You're welcome.

Also, make sure you use proper capitalization and punctuation when you write -- you can use that awful, no-capitals stuff when texting and IMing or whatever with your friends, but to be taken seriously for academic purposes, practice correctness.

Both sentences are grammatically correct, but there is a slight difference in meaning.

The first sentence, "This would greatly contribute to successful customer advices on footwear," suggests that the contribution would be towards successful advice given by customers, meaning that customers would be providing advice on footwear.

The second sentence, "This would greatly contribute to successful advice to customers on footwear," implies that the contribution would be towards successful advice given to customers. This means that someone, such as a salesperson or an expert, is providing advice on footwear to customers.

So, depending on the intended meaning, you can choose either sentence. If you want to imply that customers themselves will be giving advice, use the first sentence. If you want to convey that advice will be given to customers by someone else, use the second sentence.