Today, anyone can accept a credit or debit card - even if you are a street vendor. Swipe devices are available for smartphones and laptops - and often the devices are free. The provider charges a standard processing fee (usually 2.5 to 3%), although some have a monthly flat fee. Square was the first major provider, but other companies have joined so you have a choice in providers.
There are also online payment methods such as GoogleWallet, PayPal, and others where customers approve transactions - either directly online or through an email system.
Summary of benefits:
Level of difficulty: Low
How to implement:
It's best to be paid when you perform a service or make a sale, but if that isn't possible, you need to be able to invoice and get money - quickly.
There are many online invoicing solutions that can save you time and improve your cash flow through instant payments. Some are free, others have low cost. The key is to decide among all the choices.
Then search on the Internet under "online invoicing" and investigate 3 or 4 options.
Regardless of the system that you use, you will still need to track whether you have actually been paid. Emailed invoices can be ignored or land in "trash". Faxed or mailed invoices can also be ignored. Personal customer service and follow-through can never be replaced.