When writing a GCSE history essay the most important thing to bear in mind is the structure of the essay. The structure should be orderly and you should always make it as clear as possible what you are trying to say. For this question, it is best to start with an introduction outlining the different factors which contributed to the Germans feeling this way, and then detail each factor in a separate paragraph i.e. four paragraphs, before ending with a conclusion summarising what you have said. It is important to remember that what you will say in your conclusion should already be obvious in the introduction, and that the conclusion should merely summarise the points you have made: there should be know surprises!
Each of the four paragraphs contained in the body of the essay should explain a different factor in detail using examples. The most obvious four factors to pick for this question would be: the Germans expected the Treaty to be along the lines of Woodrow Wilson's 14 points, which seemed to promise them a restorative, instead of punitive peace; the alies didn't cross into Germany and the war was settled by an armistice, so the Germans did not view themselves as a defeated power (this later led to the stab in the back myth); the Germans did not feel that they were solely to blame for the start of the war in the balkans, so they were angry at the war guilt clause (clause 231); Germany lost its military and was forced to pay huge reparations (£6,600 million), which it was felt were designed to destroy Germany and would leave it defenceless and vulnerable to future invasion, and were also humiliating.