Not knowing much about your hair type, or current situation I would say the biggest difference maker for me was finding someone who could cut my hair well for it's type. I started embracing my natural wave, found a hair dresser who specializes in curly hair and it's been a game changer. I'm now able to wear my hair down more easily and even when I leave it to air dry, it still has great shape and volume.
In lieu of that, I love a messy bun and am not against some of those "faux" messy bun hair accessories to make it even easier.
One of my favorite hairstyles is doing a french braid. Before I got really good at it I used to create a lot of mini ponytails to have the tight look and then braid those all togethers. Super cute, great for work and perfect for summer!