I prefer paying online.Mail would be slow sometimes and cause me a late fee, so started paying online. No more paper
I created a new yahoo email for bills only. Great reminders 
I keep a list of the dates my bills are due and mark on my calender. Mine are always the same date every month, so that is super easy.
When it's time to pay bills I'll get online, open statement to make sure everything looks good and pay.
Everyone is different, but this works for me 