1. unperfect actor: an apprentice actor; an actor who does not have his lines down pat.

2. with his fear: by his fear.  is put besides his part: i.e., forgets his lines and goes out of character.

5. for fear of trust: fearing to trust myself, lacking self-confidence. forget to say: forget how to say.

5-6. forget to say / The perfect ceremony of love's rite: i.e., forget how to say all that should be said to fully express my love.

6. rite: ritual.

7. decay: grow weak.

10. dumb presagers: silent presenters of a prologue, as in the dumb show of a play.

11. look for recompense: hope for recompense (for all the pain of pleading for love).

12. has more express'd: i.e., has talked longer or louder.