I tend to buy shoes that are half a size too big anyway compared to day-to-day shoes, seems to be a better fit, but you can tighten the fit around the top of the shoe by lacing them differently. There should be an extra lace hole which isn't used at the top of the shoe, if you thread the lace from the same side back through that hole to make an extra loop on both sides, then thread whats left through that loop. little hard to explain, but like this:
I was under the impression it meant running a short distance with exagerated long strides, so running faster would be more a side effect than the actual aim. Usually do them as part of a warm up just to loosen the legs up.