Do you have a spare hour (or even 30 minutes) in the morning before school/work? If so, perhaps you could prep your ingredients for dinner later in the evening. I do this all the time.
Or, perhaps set aside your Sunday afternoon and prep up a few things. Chop a bunch of salad produce, put together a few marinades for meats a few days later, chop some vegetables for stir frys.
Or, why not make a few freezable dishes? That way, commit yourself to cooking let's say, 3 dishes a week, then use the frozen dinners for the rest. Some good contenders are lasagne, chili (although it's getting a little warm for that) and ... mmm ... I don't make frozen dinners so perhaps others will have a better idea.
Also, you should, if you're not already, assign more complicted meals for the weekend when you have more time. On weeknights, just stick to things that are good to go within 30 minutes.
Another idea is to invest in a slow cooker. That way, you can set if off in the morning, and come home to dinner already done.
Hope that helps.
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