Another very interesting aspect....
The moment we see our finished homes we get inspired to put some more wall hanging or paintings... No harm in that...
Take very small nails & dip them in the same wall paint colour & let it dry...
Call a professional carpenter or an electrician who can use a drill machine & get neat fixing of the coloured nails which you need for the new additions to the walls that you want... This will help in not making the nail too visible & at the same time a profession touch of the drill machine will not spoil the walls... Always keep a small amount of the wall painting colours as you require the same for such type of last minute touch-ups...

 I hope Yamini all ur query is taken care of :-)