It does sound so obvious, but collect information as much as possible about the area & surroundings, different schools, spanish law, taxes and regulations. A lot of things are different then you are used to.
In 2016 not even 15% of the spanish people speak another language. Make sure you do, because it will give you benefit
Every country has it's own culture and habbits. The countries in the south of Europe take it a little more easy going, meaning most of the things take a little more time.....
In spain you need to buy a house always with a lawyer, who will take care of all paperwork and legacy. Never buy without mediation of a lawyer
Spain is a fantastic country to live in. But also here in Spain life costs money. Make sure you have some savings to lean on in case things are not going according plan
The spanish schooling system is absolutely okay. Visit different schools to convince yourself which one is the right one for your children