Advice for improving lack of contrast in my images?

First, I am pretty new to digital photography. I like to shoot photos outside with only natural light, and no reflectors, between 6-6:30pm. I’m using a 5DM3 and a 24-70mm with my ISO set between 400-800, f4.0, and white balance set to shade. I like
the backgrounds of my photos blurred, and the backgrounds to have lots of saturated colors (when possible) to contrast with the subject in the foreground. I find that the contrast of my images might be lacking, and they could be a bit brighter.

1. Up until now, I have not been adjusting the camera’s exposure compensation. Will properly adjusting this setting correct the lack of contrast?

2. If the images seem to be a bit dark and lacking contrast, how do you know how many stops to boost the exposure compensation? Is it just trial and error?

3. Will using a light meter make this process prescriptive where there is no real thought to what settings to use?

Thank you.

example photo please? Is your subject in the shade? Where are you? 6:30 here is dusk. So what kind of light do you have in your loaction at that time.

The very first thing you need to let us know is what post processing are you using?

From your question, it sounds like you want a properly contrasted photo SOOC.