Hi, I’m new to blender but I’m catching on ok
I know that there have been loads of threads about this but they don’t really solve the problem. When I set smooth a model I get some weird black smudges on my model. People say that it will go when you render it but its still there.
Im doing modelling on my course and I really need help on this, its driving me insane 
If you could help that would be great
there are probably a gazillion threads about this exact problem. Without a picure I’d say the problem can be causeb ty a few things
The most common reason is that some of the normals are inverted. Select everything in edit mode and press ‘Ctrl + N’ to recalculate the normals to point outside
An edge has more than 2 faces connected to it. This is not good, so remove one of the connections and recalculate normals like in step 1 if necessary
Long and narrow faces. Add more geometry to make the faces more square.
Smoothing over too sharp angles. Use autosmooth, edge split modifier or don’t smooth the faces closest to the sharp corner
If all else fails, try select everything (or only the relevant area) and press ‘w’ -> ‘remove doubles’ and then recalculate normals if necessary
If this doesn’t help, paste an image or the blend file so people can have a look at it