(Note: this is a collection of the meanings attributed to the cards by some occultists in the past centuries. It does not reflect my own study or opinion of the cards. It is only meant as a quick comparative reference as I develop my own take.)

Paul Foster Case (and Ann Davies)

In Tarot divination the key ideas related to the Three of Wands are: mental energy, leadership, ambition, determination. It is a card related to the realization of hopes and of success after struggle.
Well-Dignified: it stands for courage, persistence, pride and nobility.
Ill-Dignified: it represents conceit, arrogance, insolence.
Keyword: Established strength.
(From the Oracle of Tarot course)

A. E. Waite

A calm, stately personage, with his back turned, looking from a cliff’s edge at ships passing over the sea. Three staves are planted in the ground, and he leans slightly on one of them. Divinatory Meanings: He symbolizes established strength, enterprise, effort, trade, commerce, discovery; those are his ships, bearing his merchandise, which are sailing over the sea. The card also signifies able co-operation in business, as if the successful merchant prince were looking from his side towards yours with a view to help you. Reversed: The end of troubles, suspension or cessation of adversity, toil and disappointment.
(From The Pictorial Key to the Tarot)

Aleister Crowley

The Three of Wands is […] the Lord of Virtue. The idea of will and dominion has become interpreted in Character.

[…]

This card refers to Binah in the suit of Fire, and so represents the establishment of primeval Energy. The Will has been transmitted to the Mother, who conceives, prepares, and gives birth to, its manifestation.

It refers to the Sun in Aries, the Sign in which he is exalted.

The meaning is harmonious, for this is the beginning of Spring. For this reason one sees the wand taking the form of the Lotus in blossom. The Sun has enkindled the Great Mother.

In the Yi King, Sol in Aries is represented by the 11th hexagram, Thai; its meaning is identical with the above description.
(From The Book of Thoth)

Golden Dawn’s Book T

A WHITE Radiating Angelic Hand, as before, issuing from clouds and grasping three wands in the centre (two crossed, the third upright). Flames issue from the point of junction. Above and below are the symbols Sun and Aries.
Established force, strength, realization of hope. Completion of labour. Success after struggle. Pride, nobility, wealth, power, conceit. Rude self-assumption and insolence. Generosity, obstinacy, etc.
Binah of HB:Y (Pride, arrogance, self-assertion).
Herein rule the Angels HB:HHShYH and HB:a’aMMYH.

Etteilla

Enterprise
Upright. This card, as far as the medicine of the spirit is concerned, means, in its natural position: Enterprise, Undertake, Begin. – Usurp, Seize. – Boldness, Temerity, Fierceness. – Imprudence, Undertaking, Bold, – Committed, Embarrassed. Bewildered. – Paralyzed, Effort, Experiment, Attempt.
Reversed. Interruption of misfortune, torment, sorrow or toil. – End, Cessation, Interruption, Pause, Rest, Influence, Intermediary, Intermittence.

MQS