The new moon is on Monday. Here in Alberta it's at 12:14 p.m. so we have from then until 12:14 p.m. Tuesday to get our abundance cheques written and salted away.
Cheques are written on the new moon because that's when the moon begins growing toward being full, like in the above photograph.
Once the moon is full it wanes and any cheque written then would have the opposite effect.
Remember, don't put a date on the cheque, make it out to yourself, write "Paid in Full " in the areas devoted to amount, and sign it "The Law of Abundance."