A white cotton long sleeved top is a MUST in your wardrobe. I haven't found one exactly right for AV yet, but once I do... I'll want to live in it, and hopefully you do too.
Anyhow, a white shirt paired black and white gingham is a CLASSIC and timeless feminine style outfit pairing. Add a classic boater straw hat (seriously, a straw hat will never be out of fashion, it is SEASONAL, but it's timeless).
I love this outfit because it can easily be worn in summer and transition to Autumn. The front view of this outfit (click on the image source link below) shows that the skirt has a wrap style waterfall ruffle, the belt has a logo, the outfit is worn with sneakers, and she's wearing lightning earrings. THOSE elements are TRENDY, not timeless. This is why I chose this photo for the outfit inspo and not other angles...
To keep your look timeless opt for very simple accessories. Don't wear things with logos and emblems (you are not a billboard) and always keep jewelry simple and minimal!
Image source: Couturezilla