Help your children to develop disappointment muscle even if they become unhappy for some time.
When your child interferes in your work or conversation to seek attention, tell him that you love him but he needs to not interfere. So satisfy his seeking attention mode but be strict in enforcement. Be kind and firm. Connection before correction.
Don't be inconsistent with your expectations. For example allow one action and then disallow the same action another time.
If a child in insisting on something you want to discourage, don't give in even if he cries. After two minutes, give him alternate options. Most of the time, he will pick one of the options and stop crying.
Lead by example. If you want him to read, read. If you want him to avoid mobile, avoid yourself.
Children are not interested in the price of things you bring for them. They are happy that you brought something for them.