The Wikipedia page on the Crusader Battle ("Operation Crusader")

Someone has spent a good bit of time writing about the Crusader Battle (they call it "Operation Crusader") on Wikipedia. I would say, in addition, that the British started the battle with a reasonable plan. The problem was, when Rommel didn't react to the initial movements, the inexperience British commanders didn't know what to do next. The old saw about plans not surviving the initial encounters holds here. The 7th Armoured Division commander, General Gott, seems to have assumed that the Germans were not a threat and proceeded to disperse his armoured force, even sending squadrons off, independently. The Germans knew better than to do such things, and kept the Afrika Korps relatively concentrated. They beat the British armoured forces in detail. It was only when General Auchinleck took charge and attacked the Germans with concentrated force, that the Axis forces were beaten. He didn't even really use armoured forces to do the job, either.