I tend to use VNAV most times. Enter data in the forecast winds page and the QNH. Start the descend around 5-10 miles before your TOD point by selecting DESCEND NOW.
Have your destination in the FIX page to get a direct distance to go and back this up using the good old 3xFL method(remember for this to work your ROD must be 1/2 your GS ie GS 440kts then ROD must be 2200fpm.
Also its good to have a GATE where you must aim to be at a certain speed and ALT.Give yourself 10-15 miles for desceleration.
Another trick which also works a treat when excecuting a NON PRECISION approach is the following. DESCEND PAGE line select 3R. Here enter ie RW27/00250(must be 4or 5 digits otherwise gives a FL) where the rwy27 elevation is 200ft + 50ft gives 250. Underneath it will give you the ROD required to be over the threshold at 50ft.