Newbie question about boosting skills

Im sorry to even have to ask but im at a loss here. I just started playing wotlk and i have no clue how to boost my fireball damage. Im a lvl 10 mage (blood elf) and im not sure what im doong wrong but the damage is still super low which means i die pretty fast if more than 1 monster attacks at once. Ive tried looking it up and apparently im missing something. Thanks in advance for any help.

You go to trainer to learn higher ranks for spells. Also you should use all kinds of spells to freeze enemies in place/slow them to kite. Mage is very squishy and dies fast if you let enemies attack you.