With bicultural parents becoming more widespread (esp. in big cities) it’s becoming common for kids these days to self-learn more than one language by the time they start speaking. Since, both the parents speak a different language; they resort to English as a common tongue. The result is a child who is proficient in two or maybe three languages by the time they start speaking.
Young kids are natural at picking and learning a language. They have the ability to speak a language or two without any sort of conscious learning, unlike adolescents and adults. They are self-motivated enough; their goal being, to communicate in order to put their message forward and get what they want. That’s why the idea that a certain language is difficult to learn or pick doesn’t exist in their heads. It’s an idea developed later on from other adults resulting in theself-learning handicap they develop over time.

Keeping that in mind, the key is to start early. It’s about taking small steps at a time and going at a pace that’s just right for your child. In fact, learning centres like Kumon put so much emphasis on the ‘just right’ level that they actually take diagnostic tests to assess individual kids before they start their coaching.
Rather than forcing the language on your child, it would be more beneficial if you put it organically in their learning process. Communicate with them in English. Don’t expect them to pick the cues early. It will take some trial and error. Don’t try to correct their grammar. Pointing out their mistakes will only make them more conscious. The key is to make it seem more like an act of communication rather than a process of learning. Once they get the hang of it, they will be confident and more positive.
Start with single words and actions like ‘come’, ‘go’, ‘sit’, ‘stand’ etc. To make it fun you can make a game out of it. For example, they are supposed to do what you say be it to ‘sit’, ‘stand’, ‘jump’, ‘twist’ all of these commands and more in any order. It will also stimulate them mentally and physically while learning something in a fun way. Once they are comfortable with single words, start using basic sentences like ‘what is your name’ and ‘how old are you’.
The mistake that most parents make while trying to teach English to kids is exposing them to endless hours of rhymes and English songs in various video streaming sites. You need to understand that young kids learn through interaction and communication and the downside to videos is that its one-sided communication. Keep such videos for later to improve their pronunciations.
Make daily communication in English an exercise they are always up for. You can make it a rewarding exercise. Keep toffees with various colour wrappers. Ask them what colour is it. If they answer correctly they can have it. These are the type of positive reinforcements that help your kid learn while having fun.