a simple guide:
buy glycerine(make shift VG) and flavorings(usually its in PG form) from phoon huat making sure the flavorings are not oil by doing water test (drop into water see if it floats or something ideally it should dissolve into it)
mix about 10-20% flavoring to amount you want-flavoring of glycerine
shake and shake, open sniff then test. (usually it will turn out bad)
Check out susan's post and look for recipe online to try
Once confident upgrade to better quality flavorings from TFA, capella, flavorart etc and also PG to balance the ratio