Noob mage

[bukimi]

There is no point in investing in Alchemy so much when you cannot upgrade your spells.
It is really important to have Level 3 of all magic schools as fast as possible to have a few "best" spells without investing a lot of crystals.
For example, Level 3 of healing, stoneskin and Fear are really useful.
The same with resurrection, all summoning and damaging spells (not worth casting on low levels).
You will find lots of crystals on every island so they will be enough before Alchemy will be useful.

Destroyer is not a good idea until you want to get to higher magic.
(or later in the game when you have really high intellect)

Try to invest some runes in mana recharging abilities (concentration or transmute)

Generally, remember to kill weaker stacks on every island and then go back to tougher ones. Do not fight with enemies where you will get heavy losses.

Check list of overpowered tricks. There are many you may find useful.