I’m a working parent and only have time to teach my daughter at night. She’s very attentively pay attention to the flashcards but i don’t know how many words and method to teach her effectively. Can someone advise me. thanks alot
It is usually a good idea to go with what the child wants. My son is very good at letting me know when he’s had enough. Start with 10 words, if she still seems interested, try another 1 or 2. If she’s looking away at card 7, show her 6 cards. When she starts looking away then stop one card BEFORE you get to that point - always keep 'em wanting more!
I find that my son always knows when he’s had enough - and will let me know, too! Don’t worry about ‘having’ to do a certain number, all kids are different. It may be as she gets more mobile that you only show one or two cards. If this is the case, you can set up a ‘word hunt’ around the house - place several cards around the house and get your daughter to find them with you. It is not quite the same as flashing, but if flashing won’t work…
Whatever you do, don’t force her to do cards - they should be FUN lol lol lol
I agree. Start with 10. If she can sit through that then its a great start. If not then lessen the amount.
Flash them fast. Like this: http://downsyndromeupupupandaway.blogspot.com/2011/05/fast-flashing-method.html
Have you tried to download the two week trial of Little Reader? All of the flashcards and curriculum are built in so you don’t have to worry about this sort of thing unless you want to. 
You just hit Day 1, Play, and so forth for each day. It can be used once or twice per day (ideally twice) but any exposure is far better than nothing. It has pictures and video clips built in to demonstrate meanings and keep your child interested.
But to answer your question, there is no 100% right or wrong answer, just follow your child’s lead!