A spelling bee is a competition where contestants, usually children, are asked to spell English words. The concept originated in the United States, and is usually perceived to be a solely American practice.
You can choose the best one from the below ones.
1- Best way to memorize is read a word, or a spelling three or five times, then have someone quiz you, and even better, have someone quiz you, and instead of saying it out loud, write it in a word doc. or something...
2- You should pay attention to word orgins. If you know what language a word comes from, it makes it easy to spell even if you have never heard of the word.
3- Get someone to read random words from a dictionary.
4- Study the latin root words used for prefixes and suffixes.
5- Go through the spelling list and see which words he needs to work on. Then, use those words and pretend to be in a play or movie. Use the spelling words (look it up and find how to pronounce it) and be very dramatic. Make sure to use them correctly. After that, little theatre is over. say the words and tell how to spell it, (part by part. ex: five words at a time)
Then, you can repeat that over and over again until he gets it.
6- It is more important at this point to address his low-self esteem, or he won't even be able to study any of those words. Let him know YOU find those words extremely difficult, too, and celebrate/reward him every time he learns even one of them. Make the learning extraordinarily fun. Downplay the importance of the Spelling Bee. It's just a game. Let him go into this with a healthy perspective. I lost a spelling bee in the fourth grade and won it in the sixth grade because the prior experience gave me confidence.