Longer Conjuration Duration?

[Chenni]

First time ESIV player. So how do you make your conjurations last longer (besides using only light armor).

On Skyrim you just get the right perk and it's done. But how about here?

[psychotron666]

Once you get access to spell making (can get into arcane university or frostcrag spire) you can create your own spells with custom durations