Here are 4 simple rules that work 99% of the time. Remember them and think over examples yourself and you will have mastery in 5 minutes.
Rule 1: Many English words that end with TY can be made into Spanish by changing TY to DAD
For example, HUMIDITY is HUMEDAD, CITY is CIUDAD
Rule 2: Many English words that end with ATE can be made into Spanish infinitives by changing ATE to AR
For example, CREATE is CREAR, ANIMATE is ANIMAR
Rule 3: Most English words that end in tion can be made into Spanish by changing TION to CION.
Only remember you need to make sure you pronounce the O clearly and with a bit of a punch, like ON (not un). When writing with a Spanish keyboard O will have an accent over it. For example, REVOLUTION is REVOLUCION, EMOTION is EMOCION
Rule 4: Many English words that end with ic can be made into Spanish by changing IC to ICO.
For example, CIVIC is CIVICO, ATOMIC is ATOMICO