Google provides a free keyword research tool to easily see what keyword phrases are popular. The tool is here:

https://adwords.google.com/select/KeywordToolExternal

Using it is very easy, type in one word or a phrase that is of interest, and then it will show you all combinations of search phrases with that word or phrase in it.

So, if you are optimizing a page for tahiti, then put tahiti in the search box and you will see results like:

Google Tahiti Keywords

Then, to see what the competition is for any keywords of interest, you can use Google directly by searching for the phrase in quotes. For example, if you decided you wanted to write a page about Tahiti and French, you could google:

"tahiti french"

in quotes to see how many "competitors" there are for that phrase. At the time of this writing there are around 350,000 web pages with that exact phrase (well, that's what Google shows but it may not be very accurate... it is a good ballpark figure though).

Choose phrases with that are relevant, are popular, but do not have a ton of competition...

Good luck and enjoy using the free keyword research tool from Google!