Don't get too cocky.
Seriously, though, that is an important factor. I had some relatively proud feeling during my first solo and my performance suffered as a consequence. Safety is the #1 factor in flying. Thoroughly check your aircraft and constantly monitor for traffic.
What I do when I solo is I talk everything I do out loud. This helps me to focus my mind on the multitude of tasks that I'm doing. I talk as if I'm telling my passengers what I am doing or as if I'm telling my copilot what's going to happen next. Of course, I would never bring anyone in the plane with me!
Be polite too. If you are at a towered airport, everything will go smoother if you are polite to the controllers. If they tell you to do something that you don't understand or are uncomfortable with, tell them so and, if possible, give an alternative. We have parallel runways at our airport and I've asked the controllers at least a couple of times if they'd prefer me to swap runways because of traffic I'm uncomfortable with. They are almost always appreciative of this and it makes their day better. Controllers work hard and stress a lot to keep us safe, even when we are, quite bluntly, stupid.
Have fun! Be safe! Your first solo is unforgettable. Oh, and be patient on your landings. You'll feel like you are floating significantly because your instructor isn't there. Flare normally, glide steadily in ground effect, and let it settle itself on the ground, and you'll get those kiss on landings.
Regards,
Zach
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