GST/HST Tips:

Keep your invoices.
One of the major reasons for GST/HST reassessments is improper input tax credit documentation. CRA GST/HST auditors require proper invoices to support input tax credits. For example, if the input tax credit is supported merely by credit card slip, and not the invoice, it may not be allowed. The source document should show the supplier's GST/HST registration number. This is not available on credit card receipts, bank statements, and cancelled cheques, which some businesses attempt to use as substantiation for their input tax credits.

Remitting GST/HST on taxable benefits.
GST/HST must be remitted on an employee taxable benefit unless the benefit is zero-rated or tax-exempt, such as the benefit on low-interest loans. Taxable benefits that are not exempt include automobile standby charges and operating expense benefits.

Sale of Passenger and Motor Vehicles.
Individuals or partnerships that are registered for GST/HST must collect GST/HST on the value of a passenger vehicle traded in when the passenger vehicle was used 90% or more in commercial activities. When trading in a motor vehicle, if it has been used greater than 50% in commercial activities, it is also subject to GST/HST. Corporations registered for GST/HST must collect GST/HST on the value of passenger vehicles or motor vehicles traded in where the commercial use was greater than 50%.