1. Buy patterned skirts that share some of the same colors. That way, you can mix and match shirts, cardigans, shoes, and accessories. The look is completely different without spending an exorbitant amount on an entirely new outfit.
2. When you can't experiment with color, experiment with cut and texture. In the looks below, you'll see a cardigan with a little ruffle, a short sleeved button up, and a lace shirt. This way, I'm playing around with more than the color scheme of the skirt.
3. Pick a pattern that does not scream only summer or fall. Pick a pattern that works well for any season. Instead of choosing a floral pattern with a white background, which seems more "spring/summer" to me, I picked one with a navy background. It has enough color to work for warmer months, but it's not so light that it looks awkward in the winter. (For confirmation, I provided you with a previous look from the winter.)
The Skirt: Francesca's
Look 1 (casual Friday): tank + chambray + sneakers
(Tank: Target / Chambray: Old Navy / Sneakers: Converse)
Look 2: colored cardigan + neutral tank + colored flats + pendant necklace
(Cardigan: New York & Co. / Tank: Target / Flats: Target / Necklace: Old Navy)
Look 3: colored top + colored heels
(Top: LOFT / Necklace: Old Navy / Shoes: Dana Buchanan via Kohl's)
Look 4: lace top + nude heels + statement necklace
(Top: Old Navy / Heels: J.Crew Factory / Necklace: The Limited)
Look 5: white button up + big belt + metallic flats + pendant necklace
(Top: LOFT / Necklace: Lauren Conrad / Flats: Audrey Brooke via DSW / Belt: New York & Co.)
Look 6: colored sweater + leather jacket + braided belt + tights + booties
(Sweater: J.Crew Factory / Belt: Francesca's / Booties: Nine West / Leather Jacket: Wilson's Leather)