Affiliate Marketing Secrets

I got a hold of a couple of long tail keywords that are related to one another with low competition. They are phrased differently and some are different but still relate to the niche. So basically what my question is do I pick one of those keywords and re-use it over and over ( to where it makes sense don’t mean stuffing it) or do I combine those different phrases and use all of them. What you guys think is more effective?

Hi,
I’m rewriting the content for my lead generation property website which is voluntarily down (because the current host is in Indonesia or somewhere and load times are pathetic!!).
For my new content and site, I have been asked to add the key phrases into the content of the site but just cant seem to put the phrases in because they are grammatically incorrect (even so, they are the most searched for phrases in the niche i work).
Does the phrase in the content have to match EXACTLY or can i change “Sell House Now” to “Sell MY House Now”?
Any help would be great!!!!!
Thanks