To prepare a spell to cast it using a metamagic feat or feats first you
should determine how many additional levels you will need for the spell. For
example, an extended spell uses up a spell slot one level higher than the
spell's actual level. So for a wizard to extend an armor spell they would
need to prepare it in a level 2 slot atleast. You can use mem 1 2 armor. An
alternate way to do this would be to start with your memorization list empty,
and to have all of your metamagic feats turned off. As you memorize your
spells, when you come to spells that you would like to use a metamagic feat
with, turn those feats on and memorize the spell. The code will put the spell
into the correct place for you.
Also, to use metamagic feats you need to be sure to have them activated
before you cast the spell. This is done via your 'combatmode' settings. It
can be useful to automate this process using aliases to change combatmode.
For our armour example you could use alias armorup combatmode +extend&cast
armor %&combatmode -extend. This will allow you to use armor extended and it
will turn off the extend feat when you are done. The % allows you to target
other people if you wish when using the spell.
The following are metamagic feats that improve magical abilities: