Tell runner as he approaches third "BE SURE TO TAG THIRD" and point at the bag. As runner leaves third heading home the coach should yell out, "BE SURE TO STEP ON HOME PLATE!" This may seem like you are treating the players like children but I have never had a runner fail to tag the home plate when I have called this out.
If it looks like a play could be made at home plate advise the runner to slide and tell them which side of the plate to slide to.
No.2: Tell runner as he approaches third from second to:
SLIDE - Hold both hands out wide apart with palms down. All players should slide if there is any possiblity of a play on him.
STAND UP - Hold both hands out wide apart with palms up.
GO HOME - Windmill motion with left arm.
Congratulate player on hits, baserunning, etc.. But - do not touch (i.e. slap hands or "high five") a player unless umpire has declared "Dead Ball" or "Time".
Tip No.3: Provide signals to batter.
Provide an activator and a validator sign. An activator is a sign which tells the batter that the next sign is the real sign. A validator is a signal from the batter back to the coach which tells the coach that the batter understands the signal. A "thumbs-up" from the batter is a good simple validator.
We have our batter tap his helmet to show that he understands the signal. Early in the season you should keep the signs fairly simple. By having an activator sign you can mix up three or four signs well enough that other team can't decipher them in one game. There are several good articles by Brian Priebe on this website about signs. Check out the baseball articles page.
Remind batter of the balls and strikes count - both verbally and with your fingers.
Tip No.4: Give your players (ALL YOUR PLAYERS) the opportunity to score. (This includes the slower baserunners.)
Be cognizant of the third baseman's and shortstop's depth. Know what the shortstop does when the batter bunts. If the third baseman charges a bunt and the shortstop does not cover third then you have an excellent opportunity to steal third.
When you get a baserunner on second you should have your batter square around early as if to bunt. When the third baseman charges it leaves the base unguarded and the baserunner can easily steal third.
In most cases I give the batter the signal to fake a bunt and pull back with the hope that not only do we get a runner to third but we may also get a ball instead of a strike.
Also watch the catcher and the pitcher closely. How quickly does the catcher return the ball to the pitcher? When the runner on third base fakes an attempt to go home does the catcher "walk" the runner back to third?
If he does and then throws the ball to the pitcher there is an excellent opportunity to steal home since no one is covering the plate at that point. The pitcher will have to attempt to run the runner down or throw to the catcher who is also racing towards the plate.
When your runner comes off of third what does the third baseman do? Does he come in behind the runner to cover the bag at third? If so, you should be sure to warn your baserunner so that he doesn't get caught straying too far off the bag. Remind your runner not to turn his back on the pitcher.
Often the younger baserunners will turn their back on the pitcher or catcher and walk back to the base leaving themselves vulnerable to a quick throw to the third baseman. Remind him that he can dive head first back to the bag.
Tip No.4: Help players keep their cool.
Do not allow your batter to get upset about a called strike that he disagrees with the umpire. Some players can become so upset with a call that they give up and are easily struck out on the next pitch.
It is your job to notice a player that is upset and to request a time-out if needed to settle him down. Its important that you take the time to remind the player that no matter what the outcome this is still a little boys game.
I try to know my players well enough to know what will make them laugh or at least what will break the tension in their mind. A quick joke told with your arm around a player can make all the difference while reminding a player to only swing at strikes will do little good.
If there is a runner on second and third you need to remind the runner on second that the runner on third is his key. If that runner advances only then can the runner on second advance.Find a Baseball camp to take your game to the next level.