Addition is often one of the first steps children grasp when learning about calculating with number. From an early point in the Foundation Stage curriculum, children start to join groups of items together and count the total amount. A key building block for this to be able to happen is therefore the ability to count efficiently and accurately. For more details about how you can help your child develop their counting skills, visit our number and counting page.
What can I do as a parent to help my child?

Play games with two dice.
Let your child play with small coins and encourage them to add them together.
Practise recalling the sum of two single digit numbers. 

Should I teach my child my own method?

As long as it doesn't confuse them and you know exactly how it works.
The methods we have chosen to use are ones that we believe will help the child to develop the understanding. Ask your child to explain how their method works; then you will know if they really understand it.
In order to develop good skills in addition, it is vital that children learn number bonds to 18 (each single digit number added to each other single digit number and itself). This will allow them to develop the skill of column addition quickly as they will already know the answers. 

The next stage would be to learn all of the number bonds to each number to 20, including 2 digit + 1 digit - eg 14+4=18.