This may be common knowledge to most of you but here is a way to practice casting without having to rest.

Be warned it requires Sulfur - if you don't have sulfur equipped one of the spells will not cast.

The process is similar to the cannibalize spell of shaman in EQ1 for those that played it.

The spells you use will be self heal and health to mana (25 lesser magic required).

If you are doing it live you will cast mana missile until you are down 1/4 of your mana bar (3/4 full) then cast Health to Mana, then cast Heal self, then cast Health to Mana, then mana missiles until heal self cycles then mix the 3 spells for maximum efficiency. You can pace yourself so between regenning in town and the spells you can keep going without having to sit.

If you were going to macro it you could put in sufficient pauses to keep macroing without sitting down. At least as long as you had the sulfur.