What can we do to avoid chargebacks disputes and all of that?
Avoiding chargebacks is not something anyone can do. You can minimize them and take steps to protect yourself, but realistically when you get on the wrong end of a dispute there is little you can do.
If the card is stolen, you're fucked.
If the customer says "item not as described", you're fucked.
The only way to prevent charge backs 100% of the time is to accept a payment method that you can't chargeback, like bitcoin, liberty reserve, western union, money gram, bank wire, bank deposit, cashiers check, money order, and cash. (off the top of my head)
Of course, doing that will limit your sales because people want the security and ease of paying with a credit card. Accept credit cards, just make sure you have a very good credit card agreement, capture a signature, make sure the address matches 100% including street name, number, and zip code, and get an exact match on the name of the card. Make sure the services you provide (or products) are clearly outlined and make the customer agree to those terms digitally. You can even go as far as to use a service like docu sign to have them agree to a contract.
Even if you lose a chargeback, that doesn't mean funds can't be recovered through other methods, such as collections or through the courts.
A good credit card processor helps as well... but with chargebacks, often times you're just screwed. It doesn't happen that much, but when it does, it sucks. I love stripe. It's easy, and they charge a small fee for chargebacks. You can program your own checkout system.... it's wonderful.
P.S. Good luck. Starting a business with friends is the quickest way to make new friends... if you catch my drift.