Exercising the use of verbs is vital when it comes to mastering Icelandic grammar. To begin with, Icelandic verbs are categorized into four classes based on their conjugation, namely strong, weak, irregular, and preterite-present verbs. Exercises for these vary from class to class.

A simple exercise could involve practicing the conjugation of a regular verb in its present tense. Later, it can be conjugated in past and future tenses. Following this straightforward pattern enables students to understand how verbs alter depending on the time of action.

In advanced exercises, students can focus on the four conjugation classes individually. For instance, strong verbs can be practiced through various forms in different tenses. This type of exercise is more complex as it requires thorough comprehension of the radical vowel changes that occur in these conjugations.

Irregular and preterite-present verbs would enhance students’ proficiency further. Engage in exercises that involve their unpredictable patterns and exceptions might seem challenging initially, but with practice and memorization, the fluency is achievable.

A common errors students make involve not recognizing reflexive verbs, thus exercises on reflexive and non-reflexive verbs differences can greatly aid comprehension.

Interactive exercises, such as sentence formation, can efficiently cement acquired knowledge. Overall, constant practice through diverse exercises is crucial to mastering Icelandic verb usage.