I recently pinned this idea from Sewing in no mans land and had to try it out as it looked so effective. I had this white t-shirt that I'd made with the Jalie 3132 pattern. It was looking a bit plain so I spruced it up a bit with the chevron applique. I love it.
The tutorial I (kind of) followed has a downloadable chevron pattern, but I made my own as my printer is out of ink! I only had interfacing/webbing that was fusible on one side, rather than both sides, so I fused the taupe jersey knit fabric to the interfacing, then pinned that to the t-shirt and sewed it on. Easy.
Finished just in time to enjoy some late afternoon sun. Lovely.
P.S. I altered the Jalie pattern slightly by lowering the neckline and adding a fabric band around the hem.