Jimmy,
back to your original question...
When performing the Kihon, break it down to segments ie when there's a natural break in the combination such as the stepping back etc. use a short pause, this allows you to gather yourself for the next bit, plus gives you a short breather, which will alow you to give more 'Kime' on the punches (especialy the last punch of each segment).
NOW THIS IS VERY IMPORTANT....
Perform the Kihon like what you've been taught during the training sessions.... Sensei always does a couple of the combinations, and when you grade, he wants to see if you have listend.
Another thing, Sensei does the grading during the training sessions, so don't be tempted to coast, just go for it.
In the Kumite, you must show aggression AND control (of techniques and of the opponent), watch out for those going for ni-dan, they are the nutters; in your first fight, go mad, that will put the fear of god into the others.
Good Luck.