As for every Dhikr uttered, for every Verse recited, for every Dua made, you earn the same reward as the doer of that act.
We mostly focus our da'awah towards adults, which is something commended, however we tend to forget the existence of Mini-Muslims.
There's a Swahili proverb which translates to, " Mold the clay whilst it's still wet and raw."
Here are some basic topics you can introduce to a young one:
1. The name, " Allah " and the fact that He is above us all. Keep saying the name till it sticks in their minds.
2. The name, " Prophet Muhammad " recite the following together : " اللهم صل وسلم وبارك على سيدنا محمد"
3. Existence of Jannah which has chocolates and candies and castles and rivers of milk and honey and we can have anything we want in Jannah.
4. Character: Obedience / respect to Parents as one way to enter Jannah. When they misbehave, inform them that Allah sees this and do you wish to not get Jannah ? Link respect for parents to Jannah.
5. We are Muslims. Anything that done by other religions is not done by Muslims.
6. Value given to Quraan, touch, see the Quraan. Be a reciter and let them see that. Ask for them to bring Quraan to You. Involve them.
7. Salah. Have a mini- Salah and let them follow you along.
8. Ramadan and Sawm. Involve them on the reasons why we fast. Let them try half way.
9. Eid occasions. Be excited about the event. Make it special so they feel it's a special occasion and always looking forward to it.
10. Daily morning and evening Dhikr inclusive of Dua asking Allah for increase in knowledge, understanding and wisdom. The art of blowing over oneself. The Dua before leaving the house. The Dua whilst entering the house.
11. Masjid and Adhaan. Let them experience being in a Masjid. Let them hear the adhan and follow it as what the muadhin is saying.
12. Dua for themselves, Dua for their parents and loved ones and Dua for the whole humanity. Teach the art of asking Allah for anything and that He will grant it if it is good for him/her.
13. Islamic etiquette with regards to cleanliness, hygiene and environmental conservation
These are some of the basics that revolve around every Muslim. Be the first to introduce them and as we all are aware of the famous hadeeth: Abu Mas’ud reported: The Prophet, peace and blessings be upon him, said, “Whoever guides someone to goodness will have a reward like one who did it.”
Source: Ṣaḥīḥ Muslim 1893
Grade: Sahih (authentic) according to Muslim.
May Allah make us steadfast in our religion and help us in raising pious and kind human beings. Ameen.