Bittman raises an excellent tip about cooking efficiently in this recent article of his.
Many of you (ha, as if there are even "many" of you reading my blog!) probably already do this, but essentially the point is that although recipes (mine included) often list ingredients out with the preparation notes incorporated into the list rather than narrating out the prep work in the steps, when you're actually doing the cooking, it's most efficient to do the prep of various ingredients as you go along rather than doing all the peeling, cutting, etc. beforehand and then executing the steps all at once (an exception to this is if the cooking takes place very quickly and you wouldn't have time to do any prep between steps, like with high heat stir-fries).
For example, you might slice onions and set them to sweat or brown in the pan while you prep other ingredients because it takes several minutes for the onions to get to the point where you want to add the next ingredients to the pan. Especially when you're just cooking for yourself, you can be more flexible about the timing and results, meaning you can be more free-flowing in your prep and cooking, and ultimately more efficient in getting your meal on the table, time-wise at least.
Anyway, hopefully that's helpful to you if you don't already do it. I will add, though, that it's much easier when you've got more familiarity with cooking and don't need to rely on recipes very closely.