I run a webshop for several months now: www.sterlingsieraden.nl as you might see, I sell jewelry. I get around 50-100+ U/V every day. The one thing that is really really bothering me is the following: I am not indexed for my most important keyword, namely: 'sieraden' (which means juwelry) What the hell is wrong? It is even in the domain name! My website is found on all sorts of combinations for 'sieraden', except for the single word. Is it the famous Google sandbox? Do I not have enough backlinks? It is eating me up!
A single word keyword is pretty hard to rank for and I would expect jewelry to be a popular term in the Netherlands as it is in the rest of the world. You will need a lot of links to rank for that word. If you want to compete you just have to put a lot of work in. I'm not sure the weird sf extension on the index helps though.
It will take a long time and a lot of backlinks to rank for a single competitive keyword. Focus on two and three word phrases first. If you keep adding phrases, the harder words will look after themselves.