firstly, well done and good luck, i, too, am starting up a discus tank. Here's what i've learnt, but NOT tried out yet!!
you will need a deep tank, around 24" deep is ok, i got a 27" deep just recently, gonna be getting all the rest of the equipment over the next 6-12 months!!
they are very docile at night so best NOT kept with nocturnal fish (dont know about snails though...) such as clown loach etc
the water temp should be kept in the low 80's
filtration should be very high quality, but NOT fast flowing
subdued lighting is a good idea, try using floating and tall plants with lots of hiding places
this ones tricky, but, ph of wild caught discus should be slightly acidic, around 6.5 is what i've heard, HOWEVER for tank bred discus, you should go see the fish regularly to see how they do in the lfs water and match your water params to theirs
an RO unit is not essential but VERY VERY useful!!
using bogwood will soften the water
and also, dark, ie black, background and substrate will enhance the colours (as with all fish really!!)
keep the substrate as clean as you can, using only a fine layer if possible, some people use no substrate but paint underneath the tank black!!
hope this is of some help!! BUT REMEMBER do lots of research, i havent kept these fish yet as i cant afford the filter i want, and this is what i've learnt from my own research, you may, rightly, contradict my findings!!!
Best of luck