The diagramming and spatial reasoning are a LOT LOT harder than practise examples.....
Read whole booklet and practise rearranging sdt maths and you will be fine, in my opinion its pretty impossible to fail that original test (althought half our group did god knows how....)
Also dont think you can do much practise on spatial reasoning/diagramming, you can either do it or you cant, my only piece of advice is manage your time and try to attempt as many as possible (this is where I came up short)....