Animal taming: to befriend the creatures of Britannia. A noble and complicated profession, few who tame know everything about it.
To tame a creature, you must use the "Animal Taming" skill either with a "use skill >> animal taming" macro, or via skill gump. Once you initiate the taming process, you will speak soothing words to the creature and either succeed or fail after a few seconds. Even if you have the minimum taming requirement for a particular creature, there may be other restrictions preventing you from taming it. All of that sort of information is found in the pet database.
Upon taming the creature, it will lose approximately 10% of its skills only, not stats. This "skill loss" will only occur the very first time the creature is tamed. If the creature is released and retamed, it will not receive another skill loss penalty. If the creature is paralyzed at any point in time during the taming attempt that is successful, it will receive a 14% skill loss upon taming.
Anything that continues to present a challenge. As a general rule, anything up to 45 points below your current skill level should yield good gains. Taming creatures with different skill difficulties within your target range usually give better gains than taming the same difficulty repeatedly. You can only receive skill gains the first time you have become the owner of a creature. This script will tell you which creatures are best to tame for your current skill level.