I love my steamer insert! If you don’t have one then I suggest you go out and buy one. I bought mine at IKEA for 3 Euros! And it works just as good as an expensive one from a fancy kitchen store. You can also use a Chines bamboo steamer.
Great things with cooking with a steamer is that it goes quick and especially fish (almost) always turn out perfectly and not dry at all! The insert fits in many pots as it can expand.
For one person I often add potatoes and veggies and the fish in the steamer and cook it all. Potatoes and root vegetables needs some extra time so I steam those for about 5-7 minutes before I add the fish and rest of my veggies.
I usually grease my steamer before I use it as it gets easier to clean!