Also, just remember that you don't need to destroy a vehicle to stop it from being a threat (albeit temporarily). Immobilizing transports will force their passengers out. Preventing an enemy vehicle from shooting for a turn is often enough (unless it can shrug off those results like GK), etc. While every DE player dreams of having first turn and alpha-striking most of the enemy off the table, this will (almost!) never happen in reality. Instead, you need to use your movement and weapons (and cover, hence why LOS blocking stuff is vital) to hide from some of his army, and shutting down the rest (whether it be through stunned, shaken, etc).

When I play DE, I generally plan my movement and shooting around preventing my opponent from shooting back in his turn. Nothing more annoying than having your vehicles which can see the enemy unable to shoot due to damage table results, while the ones who can shoot are either out of range or out of LOS!