Tailor your lessons to your class's level. An elementary class, for example, will benefit most from lessons on the present simple tense and present continuous tense but will find most aspects of the present perfect tense too advanced.
Dedicate time in class to the different verb tenses according to the frequency with which native language speakers use them. Hence, a far greater proportion of most courses should be dedicated to the various uses of the present continuous tense rather than, for example, the past perfect tense which native speakers use much more rarely.
Teach each verb tense in isolation. Introducing, for example, the present perfect tense and the future perfect tense in one lesson will result, almost invariably, in students gaining an understanding of neither. In addition, concentrate on the different aspects of one tense separately. Introducing both the future and present aspect of the present continuous tense in one lesson will confuse most students.
Guide students to discover the meaning and use of each verb tense by themselves by presenting the language to them in context. A lesson on the past simple tense might begin with you asking students to read a short passage about the life of Albert Einstein written in this tense. You can then elicit the meaning and use of the tense by asking questions such as "When was he born?," "When did he die?" and "Is he alive now?" Only then should you attempt to teach the grammar behind any tense.
Conduct pair-work, group-work or full-class speaking activities as soon as is possible in the lesson. This will maximize the amount of time that students spend practicing the language rather than merely listening to you and individually answering your questions. Moreover, use reading, listening and writing activities to ensure that students fully internalize the use and meaning of each tense.
Personalize all your verb tense lessons whenever possible. After students have a rudimentary understanding of the present simple tense, for example, you might ask them to describe their normal day to a partner.