SEO Question For The Experts

Hi Everyone,
I am very new to internet marketing, and right now, my main goal is just to give people valuable information. The pennies I get from affiliate links are pretty much secondary to making sure what I am saying helps people in their everyday lives. I used google keyword planner to come up with keywords that could potentially lead people to my site to get information. To determine competition level, I looked up the keywords using quotation marks. I went ahead and wrote a post on my website using those keywords because competition was low. Now, when I look up my keywords using quotation marks in google search I end up getting a good ranking. When I look up the keywords without quotation marks I get a horrible page rank.

A made up example:
With quotation marks I search "Apples that taste good" and I find my site on the first page of google since competition low.
I then type in Apples that taste good and find my site is on page 20 or something like that because of all the competition.

Am I doing something wrong or should quotation marks not be used when determining the competition for keywords? I have read on some sites that you are supposed to use quotation marks because you get the results for all of the combination of words you type in without them. This doesn't give you a true picture of the competition. However, I don't know how many people actually use quotation marks when searching for something. I know I rarely do unless I really can't find an answer to what I am searching for.

Thanks,
JM