I was recently instructing runners on a town league team how to be aggressive on the bases in an attempt to disrupt the pitcher. I figured that if pitchers were prepared for this it may make things easier and perhaps you could mention some ways you would combat such baserunning tactics. This is part of what we covered.
...At first base, your job is to get into the pitcher's head. It's a much easier against a right handed pitcher, but can still be accomplished against a lefty. This does not mean chatter and clapping your hands. As Domingo Ayala would say, "That's Sunday League."
Become a real focal point for the pitcher and catcher. Get out to a large lead and be ready for a pick off attempt. The one way lead is the largest lead you feel comfortable getting back in ahead of the tag. Here's what's critical...You must draw at least one throw before the second pitch of the at bat. If you can avoid getting picked off, lots of good things can happen. You will split the pitcher's focus, you will upset his rhythm, you may even draw a bad throw and end up on 2nd or 3rd base before the next pitch is even thrown!
If he doesn't throw over on the first one, keep extending until he does. There will be a point of no return on these leads, don't cross it unless you have the speed to continue to second base against a good move to first by the pitcher. Most runners will not cross this point of no return.
If you have the speed and reflexes to hang out there, you are looking for one thing. If the pitcher steps off before attempting the pick off, you should be able to safely retreat. If he makes a step and throw or a jump turn and you're hung out there and you must try for second base. Another tip is to run directly at the covering infielder's glove side, then slide in to his throwing side at the last instant. If you're lucky the ball will hit your back and at the very least you can make it difficult for the infielder to see the throw and make a quick tag on you.
Another way to make your lead look further than it is and draw a throw from the pitcher, is to be deeper in the baseline. Just like you take a step toward the infield grass to make your lead look smaller before you steal a base, take a step back to give the pitcher the optical illusion that your lead is bigger than it really is.
Another key to being an effectively annoying runner at first base is to get an aggressive secondary lead. Make the catcher think about you, too! Be aware of the pitch location. Often a pitch to the left hand batter's box side makes it easy for the catcher to snap a throw down in your direction. As long as you are ready for that, it's not a problem. You may even draw an errant throw from the catcher and be on your way to second or third.
The runner at first must also be looking to read the trajectory of the pitch out of the pitcher's hand. If you read the ball in the dirt, get out to a proper primary and secondary lead, you should be able to take second base. It is very difficult for a catcher to make a pick on a ball in the dirt and still be able to make a smooth, quick transition to the throwing hand and get an accurate rushed throw to second base. Not to mention that unlike a straight steal, where the middle infielders are screaming that you are going, a delayed steal is often successful because the infielders have shifted their focus to the hitting zone, and they don't give the catcher the auditory cue "He's going!" This often results in no one covering the base! When no one's covering the bag, I like your chances! The next time you find yourself on first base, be a pest.