Re:To Limagee
Sorry for the delay, for I have been in Beijing for several days.
About the two words of 'outweigh' and 'excel', I've just given you the differences between. Actually as I have no ideas of the context the words are really in, I don't understand the sentence very well. So I gave you the hint and for you to tell which is correct.
As for how to improve your writing ability, I think there are many ways. First. you must read GOOD English. If the English you read is not idiomatic, then your English writing cannot be improved. This is always true. The second important is to immitate. If you cannot write original good English at the beginning, at least you can immitate. And you may probably need a good course book at writing in English. I don't think it matters much whether there is someone who will correct your writing mistakes. You can proofread your own work, immitate, compare and improve.
That's all that I can suggest.