Not really looking for too big an overhaul or something that has a huge fps hit.
I use skyfalls and mills
enhanced distant terrain
and some other lod enhancers that I can't remember ATM.
You could start with checking http://www.nexusmods.com/skyrim/mods/55921/?, which is a good guide for ini tweaks and more. It has a section about grass settings, for example. I'd start there, so you get the game settings as good as possible. When it comes to flora mods, I like Skyrim Flora Overhaul and Unique Grasses and Groundcovers a lot. Note that grass mods often come with recommended ini settings, which might differ from the ones in the guide.