Unique Passive - Rage: Basic attacks grant 20 movement speed for 2 seconds on hit. Minion, monster, and champion kills grant 60 movement speed for 2 seconds. The movement speed bonus is halved for ranged champions.
Unique Passive - Spellblade: After using an ability, your next basic attack deals 200% base AD bonus physical damage. (2 second cooldown).
Attack > Attack Damage Attack > Attack Speed Attack > Critical Strike Defense > Health Magic > Ability Power Magic > Mana Movement > Other Movement Items
The lowest base movement speed in the game is 325. At this speed, Trinity Force grants 26 movement speed.
The movement speed stat only increases flat movement speed, and will not interact with other percentage increases.
Trinity Force is best used on champions that have some combination of the following:
One or more low-cooldown spells to trigger Spellblade often (Udyr, Xin Zhao).
Ability to make use of a wide variety of champion statistics (Jax, Nidalee).
High base attack damage, which Spellblade amplifies (Skarner).
One or more abilities that grant flat movement speed (Quinn).
Difficulty sticking to a target.
Using multiple abilities in succession does not result in stacking bonus damage, and the bonus damage does not increase on a critical strike.
Spellblade is a unique passive. However, if Iceborn Gauntlet is used alongside Lich Bane and/or Trinity Force, it will combine the slowing field of the former with the other's damage increase. Lich Bane's proc will always take priority over Trinity Force if both are present in a champion's inventory.
Trinity Force procs Lifesteal. It does not proc Spell Vamp, however.
Cooldown start after the proc is consumed (after the attack) not after the spell is activated.