Consider the Speed ratings of your players once they are on base. Players with speed can usually steal bases and take extra bases on hits that have that option. Slower players with a Speed of four or less will probably get thrown out trying to extend a single.
Hitting
CPU pitchers with low Control ratings will throw a lot of balls. Be patient and wait for the right pitch. Tap the screen just as the ball is crossing the plate for a perfectly timed hit. This requires practice, especially with curveballs. They will veers far to one side then turn and glide over the plate as it gets closer. Once you learn how they appear, you can adjust your timing to get good swings on them. Increase your audio volume. You can hear the sound of the ball hitting the ground when it is low. Hold your swing if you hear it. Consider bunting with players that have a six or higher in that skill. A sacrifice bunt will always work when executed correctly. Note: You cannot use the bunt option if the count includes two strikes.
Do not swing if the count is 3-0, and the pitcher appears to be tiring. An easy walk still gets you on base. Use the "Batting Order" option under "Gameplan" and consider setting it to "VsLeftAndVsRight". This will make it easier to judge pitches coming in from the opposite side. Because you cannot set the batting order manually, this will allow you to have some good hitters that will bat from the better side of the plate. Use pitch-hitters in tight situations when you have a weaker batter at the plate.
Pitching
Pay attention to the hints that are provided about your pitcher. If your pitcher is still strong and has not allowed a lot of runs, leave him on the mound. If he is tiring or getting hit hard, bring in a relief pitcher.
Various strategies
Spend the bonus games you start with to complete the first league faster. Have multiple games in progress to accrue wins faster for advancing to the league playoffs. Also, various opponents will take turns at different times. When first starting, spend your money on free agents instead of draft picks. Free agents can help strengthen positions that are lacking. Get every starter to three stars or above before trying to get a possible superstar draft pick. Upgrade your coaches with defensive boosts such as Pitching Coach, Pitch Calling, Infield Hands and Outfield Hands. You may want to upgrade them first before investing in free agents, as they will improve the performance of your entire team.