what is in the front rooms? I would love to see bigger windows or even french doors. you can paint it all a soft taupe/brown with cream trim. or take the look of the windows by garage and replace those two little ones with same style. Its amazing what enlarging widows can do. what is that tiny window to? also as long as you are ripping things off, lose those angle things over garage. and then some pretty landscaping, natural grasses and teak chairs.

Can you get another angle of the property that shows where the walkway leads to and how deep the frontage is ?

Definitely start with the windows. I think spartucus has it dead on - the windows need to be differently shaped and larger. You may want to do something later to change or augment the roofline. Depending on the shade of green of your shingles, I'm guessing you could find a color that gives you a dark but similar tone for the body of the house. You may not need to replace the shingles at all.

Perhaps put the $$ you'd spend on a roof into more MCM type landscape?

Here's my sketch of what I think would add curb appeal to your mid-century ranch.