keywords demistification help

Hi,my question is about keywords because I read about their importance but I don't think i quite got the concept.
So for example if someone searches for "home repair" and there is a big competition for that keyword the chances are you wont get high in ranking.
But if you use something like "home repair table" and you see that there is no competition for that keyword and it happens that it's related with your "home repair" site would it be a good idea to use that particular keyword as a keyword?
If not what would be the best way to compete for that particular keyword or any other.
Thanks

Yeah, it's not only a good idea, but one of the main rules of SEO. Long tail keywords are much easier to rank for.

Yup.. provided there are enough exact searches in the locale you are targeting

But it is believed that, en masse, long-tail keywords can drive just as much traffic as highly competitive short-tail ones. The trick is to find the right long-tail keywords

I just want to say thank you all for clearing things up.