Many ESOL textbooks provide CDs with dialogue, speeches or lectures from the text. You can play these CDs and let your students follow along in the text. For a purely listening activity, you can require the students to close their texts while the CD is playing. Asking students questions after the listening exercise finishes, will help you know how much of the listening the students comprehend. You can correct mistakes in their understanding as you see fit.
While many company prepared listening exercises exist, they often contain very "clear" and "formal" English speech. For an ESOL student to improve her listening in daily situations, it is important to practice listening to "real" English speech. Some exercises that may prepare your students in listening to "real" English are practicing listening to and responding to correctly speech with ellipsis, where parts of a sentence will be omitted (e.g. "Told you so" instead of "I told you so"); tails, where extra information is added at the end of a clause (e.g. "He's not very good -- that guy") and back-channeling, where noises are used to replace words (e.g. "Mmm" instead of "that's good").
Though much dialogue that comes with ESOL textbooks is very logical with clear structure, in the real world students of ESOL will have to pull information from dialogues that are not so clear-cut and orderly. You can help students practice interpreting meaning from messy dialogue by playing material with real dialogues, such as talk show conversations, recorded telephone calls or conversations that you have recorded yourself having with friends.
You can help students improve their listening accuracy through this type of exercise. Play speeches or dialogues that have grammatical or pronunciation mistakes. An easy way of obtaining such material is taping your own students, whether it is the current class or another ESOL class. While playing this material to your students, ask them if they hear any mistakes. By pointing these mistakes out to your students, over time they will be able to increase their listening accuracy.