As a developer, you can propose an improvement to the network and get rewarded when your upgrade is approved. You can also create DApps on the chain and reap profits when the public begins to use them. Follow this link to know how to start. If you are simply an enthusiast, you can buy and stake XTZ tokens in the exchanges mentioned earlier and earn rewards. Additionally, you can benefit from the bounties created by stakeholders in the network. You will find information on these bounties in the Tezos Forum.