It's really interesting topic to study and you can try various techniques

First, you should remember that there are two aspects in studying vocabulary: form (spelling) and meaning. Another issue you should have good idea on is that there are teaching techniques and controlling ones. Let's discuss teaching spelling as it's easiest one and first teachers should do. (Form is visible and easier to explain). All the teaching techniques we may refer to recognition tasks since the work of learners is to recognise the form. So,

a) write a word on a board, card with a missed letter. The task for students is to fill in the gap, e.g. A_gust, Janu_ry, Febru_ry. So that silent letter is missed. Hint, write/show words one by one. As children are quite noisy and different in perception, one might get first word another one the third one. And there would be a mess.

b) write a word with a mistake and ask learners to correct it with a coloured marker. Their task is to cross a mistakeand write the right letter. hint not erase but cross. It would help them be awareof the right version and more memorable.

c) jumbled (mixed) letters. their task is to make up a word. this task could be done in pairs or groups.

As for tasks to remember meaning, use of pics and flashcards is of great importance. You should study the material on memory strategies for children: sound, colour, taste, movement, mnemonics 'Memory-Friendly Teaching' by Douglas Corin

 The technics for meaning practice are: match a word and pics, group words (fruit anв vegetables), odd one out, picture dictionary.

you should remeber as well that learners should be motivated, do your best to interest them. And all the tasks must be done at the lesson.

So, doing your research you will have two groups, one of which is control one. With this group try teaching techniques, with another one just control their knowledge. and  soon you'll see and compare their results on the tests.

Enjoy your research!

Tatyana 

Tatyana Let