And how on Earth do you achieve them?

The best way I have found is to use the acronym:

S p e c i f i c = what exactly do you wish to do?

M e a s u r a b l e = how will you know when you have reached it? (Completed the first 5 piano lessons, ran 5 miles in one jog session, etc.) 

A c h i e v a b l e = is it in your power to achieve it?

R e a l i s t i c = can you realistically achieve it?

T i m e l y = when exactly do you want to accomplish it?