You can go through a number of different tutorials to sharpen your skills as a dApp (decentralized application) developer on the Concordium blockchain.
In Setup the developer enviroment you learn how to set up the development enviroment for working with smart contracts.
In the Counter tutorial, you are going to build a simple smart contract with a counter that can be increased or decreased and where only the owner can perform the operations.
In the piggy bank tutorial, you are going to build a simple smart contract modelling a piggy bank. It should allow any account to insert CCD and only the owner to smash it, taking all of the CCD inside.
In the wCCD tutorial, you are going to get familiar with the deployed wCCD token on testnet. You are going to write a basic web frontend example that can read from and write to the deployed wCCD smart contract on testnet.
In the Voting tutorial, you learn how to create a smart contract and dApp to conduct a vote.
In the NFT Minting tutorial you will mint and transfer non-fungible tokens. The Semi-fungible tokens tutorial describes how to mint and transfer semi-fungible tokens. And the Fungible tokens tutorial explains how to mint, transfer, and burn fungible tokens.
In the NFT marketplace tutorials you will setup an NFT marketplace.
In the eSealing tutorial, you are going to learn how to seal a document, so you can prove that it was in your possession at the time of sealing. You will use a front end and the Concordium Wallet for Web to register the file hash of a selected document in a smart contract and then display the timestamp and the sealer from an already time-stamped document at the front end.
In the sponsored Transactions tutorial, you will explore how to sign a message in the Concordium Wallet for Web (or Concordium Wallet for Mobile that uses WalletConnect) and how to send the signature to a backend. You will then instruct the backend to submit the transaction on behalf of the user on-chain.
In the Smart Contract Upgrade tutorial you will deploy a smart contract and upgrade its logic. During the upgrade, you will call a migration function to change the shape of the state.
Once you are familiar with smart contracts, it is a good idea to read the Smart contracts best practices.