Once you have reached first base, your first priority is to look over to your third base coach for signs. There is nothing more frustrating for a coach than to try and give a sign and not have the player on base or at the plate looking at the same time. Get in the habit of looking to your coach for the sign right after each pitch.
Stay on the base until you have received the signs from your coach and the pitcher has made contact with the rubber. Once the pitcher has made contact with the rubber, you can start taking your lead.
When taking your lead, remember the following:
Once the pitcher has started his delivery, you want to take your secondary lead. The purpose of the secondary lead is to shorten the distance to second base and have some momentum going toward the base. To get to your secondary lead, you want to take two shuffle steps toward second base. The goal is to complete the second shuffle step as the ball crosses the plate. If the ball is hit on the ground, you just crossover and continue to second base. If the catcher catches the ball, return to first base quickly.
When the ball is hit, you quickly need to read the trajectory. If it's a ground ball, perform a crossover and run hard to second. If the ball is hit on the line, freeze and make sure it makes it past the infield before continuing on to second.