Raising IQ is not so easy. It is a mostly heritable trait, like eye color. But there are a few things parents can do to boost their child's IQ. Breastfeeding (3-5 IQ pts.), providing adequate nutrition (12 pts), and positively interacting and reading to your child. However, there are many things that can damage IQ; excessive screen time, fluoridated water, childhood trauma, separated parents from early age, excessive junk food/childhood obesity, and probably childhood vaccines (you won't find studies out there for this one, but this is my theory).