There were two main tactics used by cavalry, the Dutch and the Swedish methods.Cavalry troopers usually wore armour in the form of back and breast plates, and a pot helmet. Often a buff coat would be worn underneath this, and some kind of thigh protection - perhaps just long leather boots.
Some regiments wore heavier armour, such as Haselrigg's Lobsters who wore full plate. This was expensive and hot, so it was limited to a select few.
Cavalry weapons consisted of a couple of pistols, and perhaps a carbine, plus a sword or cutlass. The pistols would probably be fired only once in the battle, since they were difficult to reload.
There were two main tactics used by cavalry, the Dutch and the Swedish methods.
The Dutch, apparently used by the parliamentarians at the start of the war, was to advance at a trot. The pistols would be fired at the enemy infantry when in range, and then the cavalry would wheel away. Then they would return with drawn swords and initiate a melee.
The Swedish, introduced by Prince Rupert, involved charging at the gallop. Pistols would be fired at the last moment before contact was made, and then a melee would ensue. This became the prefered tactic for both sides.
During the English Civil Wars, the cavalry tended to fight their own battle. Only when the opposing cavalry had been driven off would the remainder turn and help their infantry. In fact, the royalists were notorious for pursuing a beaten cavalry force for miles, leaving the infantry unprotected on the battlefield.
Once the pistols were fired, cavalry were very ineffective against infantry with pike support. Casualties amoungst horses were severe, and several troopers got through two or three horses in a single battle.
