Prolonged exposure to direct sunlight will fade the colours in your painting. Please be aware of this when choosing a location for the painting. You might want to dust your painting regularly, so that a thick layer of dust does not build up which will dry out the paint and possibly result in cracking and peeling. Do not spray anything on the work. Dust with a soft, dry cloth. If the surface of your painting looks dry and dull, you may want to have it varnished. Varnish is a protective surface which will not only enhance the image, but will keep the surface intact and safe from cracking (except under extreme circumstances, of course). Never expose your painting to extreme heat, extreme cold, or to extreme humidity - see more at: https://www.greenc.in/art/painting/acrylic/gc_msp_00003.html#sthash.bd2hltsi.dpuf.