Know the subject. The subject of the verb determines the conjugation form. In most cases, the subject is indicated by a subject pronoun like "yo" or "usted." Sometimes the speaker does not have a specific subject in mind and is making a general statement. Such impersonal statements use passive or impersonal voice in Spanish: the pronoun "se" plus the third person singular or plural conjugation of the verb. If the subject and the object are the same, a reflexive pronoun such as "me" or "te" may be necessary.
Determine the infinitive verb ending and whether or not it is irregular. There are three verb endings in Spanish (-ar, -ir, and -er) and each has a separate form for the different tenses. In addition to regular conjugations, there are over 50 distinct irregular verb patterns. Consult a dictionary, verb conjugation chart, or a Spanish verb reference guide to ensure that the verb form is correct.
Look for mood and tense cues. Words like "ayer" or "hoy" can indicate whether the action occurs in the past, present or future. The verb conjugation form also indicates the speaker's mood or what he or she is expressing about the factuality or likelihood of what is said. Everyday conversation usually uses the indicative mood. If the statement is contrary to fact, in doubt, or hoped for, the subjunctive mood is likely most appropriate. A command requires the imperative mood.
Determine where to place any pronouns. Most pronouns precede the conjugated verb. A negative precedes a pronoun when it goes before the verb: "no me voy a peinar." Reflexive pronouns can precede or be attached to the gerund or infinitive verb forms. If the pronoun is attached, add an accent on the stressed vowel.
Check the spelling and placement of any necessary accent marks. Some verbs adopt an irregular spelling in certain tenses in order to preserve correct pronunciation. For example, the verb "sacar" becomes "saque" in first- and third-person present subjunctive because it would be pronounced incorrectly if spelled regularly. Additionally, some verb forms require accent marks to distinguish them from other forms that are otherwise spelled identically. A missing accent mark can cause the speaker's message to become muddled and confused. A dictionary, verb conjugation chart or guide provides correct spelling and accentuation.