There have been a few times, especially in my first few months of dressing Lolita, where I just had absolutely nothing to wear that I had not worn recently. Back then, there was really no way of avoiding it. When you are building your wardrobe, you are very limited, and regardless of how creative you are with your outfits, you just do not have the variety. That being said, there are things you can do to lessen these occurrences.
The first thing I do, is to look at colors I have not focused on in piece so far. Examples:
My peacock skirt has purple, gold, blue, and green. So far I have focused on bringing out the blue, but I could switch to the green, or even the purple (although the purple is the main color of the skirt). If I were to acquire a blouse, belt, or tights in the right shade of green, it would completely change the look of the outfit. Same goes with the pink in my Snow White or Sleeping Beauty Infanta dresses. Find the less obvious colors, or, if you are dealing with a solid color, find a contrasting color you have not used: purple with yellow, blue with orange, green with red (although avoid looking like a christmas tree….unless it is December…and that is your goal). Look to what is current in fashion too, you may find some inspiration with the color combinations you find there.
The second big tip, is finding a piece you have not really used yet and find a way to use it. Maybe it is a hat or bow, maybe it is a necklace, maybe it is a blouse. Whatever it is, take it out, put it in the middle of your bed and start pulling out pieces that it could work with. Play around with different combinations until you find one you like. I was doing this for a meet-up last month, but I did not finish the skirt I needed in time. Still, that outfit is in my mind now, and you may see it in the future.