I think a small window in the gable would be a nice addition. Plus, having natural light and the opportunity for ventilation in the attic (even if it's just used for storage) is something I personally would want. I'm not clear where the other possible window location is so can't comment on that.

This not so great image was taken on a rainy day this past weekend. Here's the sideview I mentioned. Thank you both for the feedback.

Cute house! Looks like a nice location, too.

A couple rough mock ups. For fun in the third picture I added some windows to the blank expanse on the side wall. Not sure what's there so windows might not be appropriate, but just in case I thought it would be fun to add to that wall.

Is this going to be an attic for storage or will it be living space? If it's just for storage, I'd skip the windows so you can use those vertical walls for shelving to organize your stuff. If it's living space, of course you need windows.

Thank you, thank you, Chicagoans! I needed a visual!!! Originally, we did have those two side windows but it's a small bedroom for two boys so we did away with them for wall space. The other lower level window you added is a tub/shower. I do love windows though. I will send a picture of the other side now in case you all wanna give more ideas:-) This is great! Thank you so much!

The addition of that main floor window looks really nice.

I think it looks nicely balanced "as is". I wouldn't add another window.

Benjesbride, no living space in the attic space, just a little bit of storage. There won't be much walking space there either.

I think a diamond or some pointed window shape would work well and be an appropriate period solution. There is a lot of empty space and you want to emphasize the angles and verticality, not fight against it with a squat, square window.
Casey

I agree with Casey as far as against a squat square window. Maybe an oval or round window or even a ovakl or round gable vent?

a couple of differently shaped windows

I think when in doubt add the window, it's great to have more natural light.

Nice house! What are the exterior materials? I'm a big fan of natural light, but since it is an attic space, perhaps you can add architectural interest with siding materials and trim, rather than creating an opening in the gable. Here's one example below, a little busy for my taste but it gives the idea.

town hall parade · More Info

I don't know construction basics, but I'm wondering is the attic ceiling or floor insulated? If it's not an insulated space, could you just use gable vents for architectural interest? I would be very cautious about investing in windows in an unusable attic space; seems like unnecessary expense and maintenance.

You can break up the gables by using trim and 2-3 types of siding. Like lap on the main level, batten above and then shingles in the peak of the gables. I recently saw a photo on instagram where a similar style home had barn lights in the gables that washed light down the exterior walls and it looked very pretty in the evening, so lights can also be used to break up the expanse of siding in the gables.

My humble attempt at a visual explanation :-)