I started reading Starhawk's The Spiral Dance after I got it a short while ago. I haven't read every day, but I try to read whole chapters at a time, plus her notes from the ten- and twenty-year anniversaries, so I get the updates right after reading the chapter, to better remember.
Today, I read chapter seven, and I might begin chapter eight before I go to bed. But I decided that instead of diving right into chapter eight immediately, I would stop and do one of her easy little suggested activities. The simplest one I can think of, besides grounding and centering which I've done for years (and her definition of centering differs from mine), is candle gazing.
The goal of candle gazing is to increase your focus and concentration by gazing at a candle flame for five to ten minutes without letting your gaze un-focus, or go blurry, crossed, fuzzy, or double-visioned. So I lit a candle, sat comfortably on my futon, and settled the candle in front of me.
At first, I thought it might be difficult. Thirty seconds seemed to take forever and I thought "I'm going to do this for five minutes?!" But it's really not difficult. You just have to LOOK. After a while, it was tempting to shift my focus and scry in the flame--it kept moving in such interesting ways I had never consciously noted a flame moving in before, and I watch flames quite a bit. But after a while, I was sure it had been five minutes, and my gaze hadn't lost focus. I determined that this was probably not a necessary skill-builder for me, and I know I have pretty good concentration, but I still think it's good to test those basic skills every now and again.
I tried doing some other focus exercises with it, then, focusing on a specific size of flame or quickness, playing with wax and heat, and dropping an energy ball onto it. There were varying degrees of success. I doubt myself, suddenly ask myself "What on Earth am I doing?" Even after eight years and several obvious successes, I still occasionally doubt my ability to repeat a feat. Still, the next thing I knew, half an hour had passed.
Get a candle and a comfy spot and try candle gazing for yourself. You don't have to do it a lot if your concentration is already good, but it's worth flexing those muscles and maybe developing some more.