Which foods and food preparation techniques can make swallowing easier?

Thicken or puree. There are several types of dysphagia, or swallowing problems. These can be diagnosed by swallowing studies. Problems with liquids can be helped by thickening the liquids. Problems with solids (especially dry solids) can be helped by using purees or softened foods.
Soft foods/liquids. Soft foods and liquids generally make swallowing easier. Hard foods such as pizza or bulky foods such as steak are much harder to swallow and can get stuck if you have a problems with a narrow foodpipe (esophagus). Blenderizing foods helps. Avoid too much spicy foods. You should be evaluated by a doctor to make sure nothing serious is going on, especially if the swallowing is getting worse.