There are boxed meals and semi-prepared meals you can buy, but I really want to start making most of my food from scratch or fresh ingredients. Especially since those box things tend to have a lot of excess salt/preservatives in them and it's probably better to avoid eating them if you can avoid it. But I do eat semi-prepared meals a lot currently since I'm lazy and there's tons available for people who live alone and want easy meals.

I feel like as soon as I get a handful of recipes down that use several similar ingredients I can make them over and over again each week and gradually try out new things. The main reason I haven't done that so far is that I'm not really sure how to make a menu like that yet that is based around traditional Japanese food (since I'm going to be cooking for my fiance pretty soon).

A typical Japanese meal almost always includes the following all on separate dishes: a main dish, a side dish, a staple food (i.e. rice, or maybe bread if it's "Western style"), and a soup (usually miso soup unless "Western style"). Exceptions are if the main dish includes one or two of the other categories (like curry or ramen or pasta).

So that means every day I'll need to have a different main dish and I should alternate between side dishes at least every other day. I can adjust the rice/soup slightly, but it's fine if the base is essentially the same every day. I know how to do that in theory, but in practice it's still kind of intimidating, especially since I don't know how to make portions appropriate for just one person and how to store the leftovers and use them up properly while they still taste good.