How do I make my own spells again Im a bit rusty at Oblivion

You need to get to a spellmaking altar. That requires you to either join the mages guild and complete the recommendation quests to get access to the Arcane University, or to have the Wizard's Tower dlc installed.

Here is a great review of how it works - http://www.uesp.net/wiki/Oblivion:Spell_Making

Remember that you can only make spells using effects that you already know and have the ability (skill and magicka) to cast.