Start with a memory from childhood. Compress it into a vignette. Anything you remember with a good degree of clarity. Be specific about what you remember. Don't worry about casting it in any certain light, just write out what happened in a short, concise manner.
This will be the end of your piece.
Now sift through your past and find a series of other memories to wave into this poem. Let them connect themselves.
See If 100, then 150 by Chiwan Choi. Enjoy.