Experience
What you want, in my experience in playing wizards, is for your spells to work. For example, if you're a transmuter that focuses on self-buffing and party-buffing spells, unless you're going to be going up against people with dispel magic and antimagic field, you don't need DC-pumping feats; you need Combat Casting, Quick Casting, Twin Spell, etc.
Dellas, as a fire-focused wizard with a lot of evocation magic, then yes, Spell Focus is an excellent feat to take because you need your DCs to be as high as possible for your evocation spells. The less your enemies can avoid taking half damage, the better. As you grow in levels, metamagic feats will also become useful. Things like Widen Spell can make burning hands useful at clearing (or at least damaging) large swathes of the battlefield, even at higher levels.
This message was last edited by the GM at 16:55, Thu 17 Nov 2016.