For a PvP mage, focus on your timing of small spells. For practice, get a friend with an archer to get a fast bow and shoot at you. You should be able to time small heals to heal in between hits. I use uo to set all my mage macros except spirit speak, which is on my mousewheel. I like last target being on the spacebar. I have small heal and cure set as cast spell > wait for target > target self. If you time it right, not much can disrupt chain healing and curing this way. Its all about timing. When against other mages, use small spells to disrupt his casting such as harm and magic arrow. If they are anywhere decent, you wont be able to get off anything much bigger than lightning unless you disrupt them and throw off their timing. All in all, practice makes perfect!