Piano tuning is quite difficult, but not impossible. If you've got the patience and the desire to learn, you certainly can. This website gives a good introduction to the theory behind piano tuning as well as highlighting some resources for learning how to do it on your own:
Thanks a lot Iemarquis! That's a useful link, but i'm not sure where to start with trying out, as I dun want to screw up my own piano, and have to ask somebody to fix it with a considerable amount of money. (e.g. changing a string here cost me EUR 80! )
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