Here is a guide to commonly used irregular verbs and how to conjugate them in the present tense.
These verbs do not follow any particular rule for how they are conjugated, however you will see some similarities here and there.
There is a list of verbs within this presentation.
1. être
singular 1st person je suis
2nd person tu es
3rd person il / elle / on est
plural 1st person nous sommes
2nd person vous êtes
3rd person ils / elles sont
2. avoir
singular 1st person je ‘ai ai
2nd person tu as
3rd person il / elle / on a
plural 1st person nous avons
2nd person vous avez
3rd person ils / elles ont
3. faire
singular 1st person je fais
2nd person tu fais
3rd person il / elle / on fait
plural 1st person nous faison
2nd person vous faites
3rd person ils / elles font
4. aller
singular 1st person je vais
2nd person tu vas
3rd person il / elle / on va
plural 1st person nous allons
2nd person vous allez
3rd person ils / elles vont