A = assess
This is your assessment - it might be direct physical assessment of the patient, interviewing the pt. re: symptoms, history, etc., analysis of lab results, or any other data-gathering.
D = diagnosis
This is your diagnosis of the patient's problems (parallel to the medical diagnosis). What "problems" does the patient have that need to be "solved" or at least addressed?
P = plan
This is your plan of care -- what do you plan to do to care for the patient and why?
I = interventions
These are nursing interventions - med administration, assessment at certain intervals as appropriate, repositioning, monitoring vital signs or other assessment parameters, treatments, patient teaching, emotional support, etc.
E = evaluation
Evaluation of your care -- are the interventions having the intended effect? (i.e. - if you administered Tylenol for an elevated temp, is the temp now normal? or do you need to do something else?)