Flashcards, repetitively writing them and reviewing them in context of your patients problems. There are a few little tricks that help a little.
Many values are 2 or 10 -20
Potassium and Albumin are the same, I try and find similar lab values.
If you are asked a lab question, its usually blatently abnormal, so even if you just remember approximately what the valus are, you should be able to pick out correct one.
Applying the labs in a disease process and in deficit and excess helps conceptualize and understand the values
while you are in clinical look at all the labs for the entire time the patient has been in the facility. When you review something over and over it eventually will stick. Also, if there was an episode of a lab being out of normal parameters, look at the chart to discern what was going on at the time and if there were any interventions required to balance the lab work. That way the numbers have meaning.