To add to Miss Kelly’s post, from a New Zealand/British English point of view it makes more sense to use “First” as well. Firstly sounds absolutely fine, but it’s a little bit childish (i.e. written in a school essay).

This is how I would edit your writing: Temakizushi is a type of sushi. First, you put rice on a sheet of seaweed the size of your palm. Next, you add any toppings you like such as tuna, salmon, avocado and so on. Finally, you wrap the toppings with the seaweed just like you would wrap a baby with a towel. I personally find using firstly, secondly, thirdly - to sound awkward. I know it's technically correct English, but as a native English speaker who has spent a lot of time around business professionals, it's just rarely used. I think it's safer not to use them since they can cause a little confusion or cause the listener or reader to start thinking about the words you've chosen instead of just listening to or reading your story. Also, I believe that "finally" sounds better than "lastly." Good job! Keep up the good work :-)

Following on from Miss Kelly's correction: 1. I also agree about First, Second and Finally in preference to the awkward 'Firstly', and so on. Contrary to popular belief, these words are in fact just as 'correct' as the options ending in 'ly'. There's a myth out there that all adverbs must end in 'ly'. This results in all sorts of overcorrection, including nonsense words such as 'oftenly' and incorrect usages such as 'Say it rightly'. 2. If Ms K will allow me to nitpick ... If you say 'such as' [tuna...], this is telling us that we are giving examples, making 'and so on' redundant. I think you should delete 'and so on'. 3. And perhaps 'wrap a baby in a towel' would be better than '..with a towel'? 4. One final thought... surely, if the tuna, salmon or avocado is wrapped up, these are FILLINGS rather than toppings?