I would have to say the best way is to try to get multiplication flash cards and go over them with your child a couple times a day and they will eventually get better at it. My grandma did that with me and now i can do my multiplication homework.
There isn't one best way. Show a strategy and see if it makes sense. If not show another strategy. For some it's best to start with repeated addition. For others they found it useful to create jump rope rhymes. For example : Eight and eight got sick on the floor.( 8*8 equals 64)
Be sure to teach your child multiplication problems in sets:3 x 4 = 4 x 3, etc. It's like 2 for the price of 1! Also, I like to keep a math facts chart from 0 x 0 to 10 x 10. As a student learns the fact by rote, I allow them to color it in with colored pencils. The student gets to take ownership of their progress.
You can also this method.. It actually makes the child understand how things multiply. Take a paper chart and draw tables (similar to a chess board) with ten rows and ten columns equally spaced.Number the rows 1-10 and columns also 1 - 10. Now give the child some beads or may be some kidney beans(dry ones). Say if ur teaching 2x2 = 4 then ask the child to place 2 beads in column 1 and 2 beads in coulmn 2 and now ask the child to count. similary 2 beads under column 3 will make 2x3=6. Also make the child to write it on a paper. They will always remember. After they understand the concept, They will be able to write their multiplication tables all by themselves !