I went to Lowe's and got two 5 gal buckets. I got grit guards from detailed image I think.
A good mitt will go a long way, make sure to take care of it. I use different mitts for different things. I think I have like 4 different mitts. One for the upper panels, one for the lower, one for the front bumper alone (bugs and stuff), one for the wheels. I actually replace my mitts on a regular basis. There comes a time that they get dirty enough that they won't do any good and will just do more harm than good. But then again, if you buy cheap ones from Autozone or something it's not a big deal. I still get microfiber ones, and I do have a couple good ones I bought online that I use more often and really take care of.
Make sure to keep your MF towels clean. I think some of these sites sell a MF towel cleaning solution. Or you can just replace them regularly too. Up to you on how much you want to spend. MF towels aren't too expensive. A regular MF towel pack isn't too pricey, but if you start to get into the waffle weave large drying MF towels, it can get up there a little, so take care of them.
'11 BMW E92 ///M3 - ZCP and DCT
'15 Ford F-250 - Lariat, 6.7 Powerstroke Turbo-diesel