Summoned creatures are your friends. This could be quite literal in some settings or with some GMs, where a caster summoning the same creature type will always call upon the same creature, or metaphorical in others – but either way, they are wonderful for support and force multiplication. A summoned creature can shore up that weak flank, provide magical assistance, act as scout or decoy (though if you generally get the same summons, make sure they are on board with the idea.) A clever conjurer with a good relationship with his summons is a frightening enemy – sapient ones will themselves go above and beyond for a friend, with minimal supervision.