(Just finished the second test for GIAC GSEC certification!)
The first test went quicker than the second because I used the "open book" clause for the second. Overconfidence in the first test caused me to get a lower grade than the second one.
Recommendations? Study your ass off! (right up until a day or two before you take the tests) If you don't have hardcopy, generate it and devote a binder to each section. Flag valuable tables/diagrams/info with stickies! Don't wait to the last minute to take the tests (like me).