I'd like to mention a few other important pieces of advice.
(1) If the revolver can be hand-cocked and fired single-action, I strongly
recommend becoming comfortable with the decocking procedure before
attempting live single-action fire. The general technique is (a) place thumb of the support [non-firing] hand in front of hammer, (b) pull hammer spur back with thumb of firing hand, (c) press trigger while retaining hammer with both thumbs, (d) release trigger, (e) move support hand thumb out of the way, and (f) ease the hammer forward with the firing hand thumb. It sounds complicated but becomes easy to accomplish with some practice. BTW releasing the trigger (step D) prior to moving the support hand thumb will usually cause the hammer block or transfer bar to move into the SAFE position, preventing the gun from firing if your other thumb slips. (More on these safety features below.)
(2) Dry-firing- i.e. pulling the trigger with no rounds in the chambers- is a common way to practice your trigger pull, particularly for double-action fire. However, there are some mandatory warnings. (a) You MUST check and double-check that all chambers are empty before dry-firing is attempted! (b) It's considered poor etiquette to dry-fire ANY firearm that doesn't belong to you, unless you ask the owner or store clerk beforehand. (c) Most rimfire [.22 Long Rifle, .22 Long, or .22 Short] revolvers should never
be dry-fired, as this can damage the firing pin. OTOH most modern (i.e. post WWII) centerfire revolvers can be dry-fired without damage. (d) NEVER
dry-fire with the muzzle pointed at another person!
(3) You are likely read or hear some earnest advice- and even a few pop-culture references- stating that revolvers should always be carried "five-up" (or "four-up") with an empty chamber under the hammer, to prevent an accidental discharge if the gun falls on the hammer. This advice should
be heeded if you're using an older gun, or certain single-action designs. However, almost all post-WWII double-action revolvers incorporate some form of hammer block or transfer bar to prevent accidental discharge if dropped, and these devices are almost 100% fail-safe. Modern revolvers can be confidently carried fully loaded.