(noob here) odd discoloration on my model, what does it mean? (model is not nearly complete btw)

whenever go into the mode that makes the faces solid (idk what it's called), some parts of my model are discolored (sort of steel-blue looking). i was curious as to why that was happening and if that is going to be carried out into a final render. thanks for any help that yall can offer :))

bonus question: what's the best/easiest way to add more detail/make a model less blocky? besides adding a load of loop cuts obviously lol. thanks
your normals are not all facing outwards, in general its a problem of the mesh recalculating them is the easiest way to solve it.
If that doesnt work out (if your model isnt solid), you can also in edit mode flip faces.