As an unperfect actor on the stage,
Who with his fear is put besides his part,
Or some fierce thing replete with too much rage,
Whose strength's abundance weakens his own heart;
So I, for fear of trust, forget to say
The perfect ceremony of love's rite,
And in mine own love's strength seem to decay,
O'ercharg'd with burden of mine own love's might.
O let my books [looks] be then the eloquence
And dumb presagers of my speaking breast,
Who plead for love and look for recompense
More than that tongue that more hath more express'd.
O, learn to read what silent love hath writ:
To hear with eyes belongs to love's fine wit.
Sonnet 23 as well as Sonnet 18 falls into the sonnet group dedicated to a young man (Sonnets 1-17 and 18-126). This young man was probably Shakespeare's first patron, Henry Wriothesley (pronounced either [raɪzli] or [raɪəθsli]), who was the Third Earl of Southampton.
We have discussed the ambiguity of the romantic (and often erotic) diction Shakespeare employs in addressing this young man. Let's leave any lingering curiosity on Shakespeare's sexuality to rest and take into consideration how effective such romantic diction would have been for Shakespeare to secure his patron's good will and favor.
Consider the extensive usage of the theater analogy. An actor who is transitioning to a full-time writing career, Shakespeare seems to be in his own element when referencing to the elements of the theater and acting. His preference of a script (a book or look that is filled with readable expressions) to a speech (a tongue or speaking part) seems to testify to his gradual but palpable transition from an actor to a playwright.
I highlighted some theatrical allusions for you: why don't you flesh them out?