Seriously, do you tether yourself with that bird? I'm 6' 160lbs dripping wet and I don't think I could stay planted on Terra Firma if I was hangin' on to that thing.
You *could* fly while holding on to the line if the wind wasn't too strong, but it would grow rather tiresome.
The preferred method is to anchor the flying line to a substantial, stationary object (like a tree, a post, a car bumber, trailer hitch, whatever) and let the kite fly anchored that way.
The anchoring method that I use is a light (ATV sized) tow strap; it's an about 1" wide nylon strap with pre-sewn loops on both ends and is about 8' long and is rated for a couple thousand pounds. I just loop it around the anchor point and clip the flying line to it using a caribeaner (the caribeaner is tied to the end of the flying line itself so it just clips to the anchor strap.) I use the tow hitch area on my truck/Trailblazer a lot because I don't have to depend on some other stationary object being at the flying site.
The (minor) problem that this presents is that your flying site must have enough horizontal space on the ground to accomodate your total length of flying line. In practice, you set the anchor point, clip the flying line to it, and then unroll your flying line (I do this by holding the spool/reel and walking away from the anchor point) until all of the line is unspooled. Then assemble the kite and clip to that end of the flying line via a second caribeaner tied to that end.
To launch the kite, you hold the bridle lines at the tow point and lean the kite (set the angle of attack) to the wind so it will generate lift, and then, while holding the flying line *down*, start walking back to the anchor point. As you walk back, you continue to hold the line down by sliding a gloved hand along the line. This keeps the line between you and the anchor point parallel to the ground and the line between you and the kite going up at the kites flying angle (this depends on the kite, how it's bridled, and wind speed.) Sliding along the line like this is like letting out line so the kite gains altitude.
To bring the kite down, you don't pull it in; you reverse the process of walking the kite line. Much easier to do.