How to optimize access to the Database?

Question

I’m doing a project where I often need to access the database to do things like:

• Load User Data (Example: Balance, Settings);
• Upload images;
• Insert/Update data.

It’s a pretty boring process to have to do the same code over and over and just change the SQL, or the Table.

I decided to make a Connection class, but within this class I only keep the Connectionstring, ends up not changing much.

public class DBConnection
{
     public const string ConnectionString = @"....";   
}

I inherit this class in all classes I need to access the Database, with this code below I update the User Balance.

using (SqlConnection sqlConnection = new SqlConnection(ConnectionString))
using (SqlCommand sqlCommand = new SqlCommand("UPDATE tblClientes SET Saldo += @Saldo WHERE Usuário = @Usuário", sqlConnection))
{
    sqlCommand.Parameters.Add("@Saldo", SqlDbType.Real).Value = Saldo;
    sqlCommand.Parameters.Add("@Usuário", SqlDbType.NVarChar, 50).Value = Usuario;

    sqlConnection.Open();
    sqlCommand.ExecuteNonQuery();
}

• How can I optimize this?
• So I don’t have to repeat this same code over and over again in my project?