The spider shots look great. They might be a little soft because of cropping or something, but still very good. Add a little contrast to the jumping spiders and call it a day! What aperture did you use for those pictures? Jumping spider photos easily get ruined by diffraction, which might not be the case here.
The fly photos are not on the same level. I have to say that flies are my favorite macro subjects, because they are difficult to capture. Especially the eyes are hard to get right, since hard light creates weird light sports with sharp edges. But anyway, better angles are the key in my opinion. I have taken around 10 000 fly photos this summer and I think that only 1 or 2 are worth showing to someone else. Usually it comes down to having something interesting in the photos like a fly eating another fly or a very special angle. I don't think that it makes sense to spend time taking pictures of flies sitting on flowers or leaves, unless of course there is something special happening.
When it comes to using a flash, I'm not sure why one would use a ring flash. Those are not great and show up as weird circles in the eyes of jumping spiders for example. Then again, what ever you use, it shows up in the eyes. I would say that stationary insects and no flash is ideal, but .... The bugs I see keep on moving, sp a flash it is then... ruining the photos.