This is the penultimate word in emplacements. The only larger emplacement you could build in 40K is for a superheavy vehicle, and you would just need to scale this up a bit. Let's get started.
* Hit glue gun and glue sticks
* Large base (I used a 12" by 6" piece of plywood, but you just need something large enough to hold your tank comfily. Don't forget your sponsons!)
* Paint and brushes
* PVA glue
* Sharp knife
1) Use the hot glue gun to stick some polystyrene to the base. See Fig. 1.
2) Trim the polystyrene to shape. Make sure your hull weaponry and sponsons have clear lines of sight. See Fig. 2.
3) Trim some matchsticks to the right height. Glue them in place with the hot glue gun. Apply dilute PVA over everything bar the matchsticks. Scatter sand over that. Once the PVA has dried, apply another dilute coat of PVAto fix it in place. Once that has dried, undercoat the whole. See Fig. 3.
4) Paint as desired. See Figs. 4&5.
I hope you like that, folks. Until next time, happy gaming!