Students of foreign language are often intimidated by the 16 different sets of verb conjugations that French has to offer. In reality, these verbs are not nearly as tough as they look, and in fact, only some of these conjugation sets are necessary for fluent speech.
Moods & Tenses
French verbs are classified by moods and tenses. Tense refers to the time that the verb is taking place. 'I do' versus 'I did'. Mood refers to the function of the verb. For instance, the imperative mood would be a command. 'You eat' versus 'Eat!' The most common mood is the indicative mood, and this is what you should focus the majority of your studying on. As far as tenses, focus on the présent, passé composé, imparfait, and futur simple.
A rule that holds over most verbs is that there is a pattern. Verbs that don't follow this pattern are called 'irregular'. The student must simply memorize these verbs, while for the remainder, you can memorize the pattern. Present tense focuses on what is happened currently. 'I (am) eating', 'I (am) reading', 'I (am) sleeping'. I will detail the standard pattern of regular -er present tense verbs here. '-e', '-es', '-e', '-ons', '-ez', -ent'. All present tense, indicative mood, regular -er verbs will follow that pattern in endings. The root of the word will always stay the same in regular verbs, while the ending will alternate. If there is a variation in these rules, the verb is irregular, and you must simply memorize the variation. Some variations only slight, while other variations may make conjugations look completely unrelated to their original form. Pay attention to which verbs are irregular (many irregular verbs carry over into tenses and moods) and the ending pattern of regular verbs.
What Next?
As stated above, you should focus most attention of the present, past (passé compose and imparfait are both past tenses and both are commonly used), and future tenses. Why? (1) One can confidently and proficiently speak using only these four tense conjugations and (2) almost all of the other conjugations are based on these conjugations. Take the conditional tense for instance. This tense is formed from the infinitive (parler, manger, dormir, etc.--the verb form with the er, ir, or re ending), with the imparfait past tense endings attached. One should eventually become comfortable with all tenses, including the archaic/literary forms (eg. passé simple), and all of the moods. The imperative mood is quite simple and save for a few irregular verbs, it can be learned in minutes. The subjunctive mood can become rather complex, though you will likely only encounter the present tense in conversation and most writing. In closing, focus your attention on indicative mood, and the present, past, and future tenses. Once you are comfortable and confident with your knowledge of these, learn the conditional tense and become acquainted with various compound tenses like the past perfect and anterior future. Learn commands by studying the imperative, and finally, learn the present tense of the subjunctive mood, and skim over the constructions for other subjunctive mood tenses.
By following these guidelines, you will save time and you will make the learning process significantly easier.