In my opinion the best way is to buy a s/s steamer - it's similar to a pan but without a handle and it has holes in the base. Put veg into this & place over a pan of boiling water (a pan which holds the steamer in place) & cover. The veg should slide off the fork but be fairly firm to the bite. If it's too soft, it's overdone, hence losing valuable nutrients which can be be greatly achieved if steamed properly. I tried one of those elec steamers with the tiers, but found them to take too long & the veg on the top tier always takes much longer again