Thuzle, I am afraid that electroplating is a bit too expensive/complicated/time-consuming for me. Nevertheless, thanks for the advice.
I shall look further into gilding as andygates suggested. If anyone else has other advice, please do tell.
EDIT:I found something called "artmetal" which is, according to its description, a liquid gilding. Will that look authentic, perhaps?

Under the same category (gilding/leaf gold) in the store (artistica.nu, not in English by the way), I found gold spray. Since it's filed under gilding I thought it might suffice.

I also forgot to tell you that along with the watch, I want to dye its chain, and in addition to that I am looking to dye other silvery objects of interest (a key, some rivets and other various things). Should I maybe do a combined gilding by using leaf gold for the watch and one of the preparations I mentioned above for the remainders?
I feel quite helpless (and hopeless). I am not very savvy in crafts (when I was a child, tape was my favorite adhesive for everything - I refused to use glue or nails).