6 stages of Customer Success for SaaS companies:
1. Retention: in this stage, you have to make sure that the customers get the desired value that your Sales Team had promised.
2. Renewal: in this stage, you have to ensure that they continue to get that value on an ongoing basis and so, they will renew your subscription.
3. Upsell: in this stage, you work towards increasing the value that the customer is getting. For instance, they sign up for more users/employees and so, your account size also grows.
4. Cross-sell: they ask for more products that you have to offer apart from what they've already bought. This helps grow the account size further. You've now become an integral part of their Business processes. They trust you and it's your duty is to maintain that trust and deliver on it.
5. Referral: they suggest other people in the industry to use your product, thereby helping you acquire more customers.
6. Testimonial: they are so happy with you that they are glad to make a public statement about how good your product is.
Remember, when you start a Business, it's not for you, it's for the customer. Don't chase money. Instead, solve your customer problems, and growth and money will follow.