Whats the best approach (design pattern) to access database in C#?

I am a newber in design pattern. Currently I am developing a system where I have a releation DB. What would be the best approach to CRUD from my DB? My current code looks like the follow (C# code):

I defined a inteface with commons functions to all classes.

namespace Model
{
    public interface ICommon
    {
        void insert();
        void update();
        void delete();
    }
}

The Common class (abstract one) implements ICommon interface and few orders methods and attributes.

namespace Model
{
    public abstract class Common : ICommon
    {
        public Guid RecId { set; get; }

        public abstract void insert();
        public abstract void update();
        public abstract void delete();
        public abstract List<Common> find();

        /// <summary>
        /// Insert or update the record
        /// </summary>
        public void save()
        {
            if (this.RecId == Guid.Empty)
            {
                this.insert();
            }
            else
            {
                this.update();
            }
        }
    }
}

Then, the proper class (UserTable class for example) extends the Common class and implements the abstracts methods and others particulars attributes.

The way that I am doing my CRUD its from StoresProcedures and SqlParameter, SqlCommand and SqlConnection. Here it is a example:

    class CustTableModel : Common
        {
            public string SerialNumber { set; get; }
            public string ApplicationVersion { set; get; }
            public string KernelVersion { set; get; }
            public string Name { set; get; }
            public bool Active { set; get; }

            public override void insert()
            {
                List<SqlParameter> parameters = new List<SqlParameter>();
                SqlParameter parameter;

                // SerialNumber
                parameter = new SqlParameter("@serialNumber", System.Data.SqlDbType.Int);
                parameter.Value = this.SerialNumber;
                parameters.Add(parameter);

                // ApplicationVersion
                parameter = new SqlParameter("@applicationVersion", System.Data.SqlDbType.Int);
                parameter.Value = this.ApplicationVersion;
                parameters.Add(parameter);

                // KernelVersion
                parameter = new SqlParameter("@kernelVersion", System.Data.SqlDbType.Int);
                parameter.Value = this.KernelVersion;
                parameters.Add(parameter);

                // Name
                parameter = new SqlParameter("@name", System.Data.SqlDbType.Int);
                parameter.Value = this.Name;
                parameters.Add(parameter);

                // Active
                parameter = new SqlParameter("@active", System.Data.SqlDbType.Bit);
                parameter.Value = this.Active;
                parameters.Add(parameter);

                DBConn.execute("CUSTTABLE_INSERT", parameters); // The code of DBConn is below.
}
}

Just to a better understanding, here it is the DBConn class:

public class DBConn
    {
        protected SqlConnection sqlConnection;
        protected string command { set; get; }
        protected List<SqlParameter> parameters { set; get; }

        protected void openConnection()
        {
            this.sqlConnection = new SqlConnection();
            this.sqlConnection.ConnectionString = "Data Source=.\\SQLEXPRESS;Initial Catalog=JYL_SOAWS_DB;Integrated Security=True";
            this.sqlConnection.Open();
        }

        protected void closeConnection()
        {
            if (this.sqlConnection.State == System.Data.ConnectionState.Open)
            {
                this.sqlConnection.Close();
            }
        }

        /// <summary>
        /// Executa o processo no banco.
        /// </summary>
        /// <returns>Quantidade de registros afetados.</returns>
        protected SqlDataReader run()
        {
            SqlCommand command = new SqlCommand();
            SqlDataReader ret;

            this.openConnection();

            command.CommandType = System.Data.CommandType.StoredProcedure;
            command.Connection = this.sqlConnection;
            command.CommandText = this.command;

            if (this.parameters != null)
            {
                foreach (SqlParameter parameter in this.parameters)
                {
                    command.Parameters.Add(parameter);
                }
            }

            ret = command.ExecuteReader();

            this.closeConnection();

            return ret;
        }

        /// <summary>
        /// Interface da classe à outros objetos.
        /// </summary>
        /// <param name="commandName">Nome da store procedure a ser executada.</param>
        /// <param name="parameters">A lista com os parâmetros e valores.</param>
        /// <returns>Numero de registros afetados.</returns>
        public static SqlDataReader execute(string commandName, List<SqlParameter> parameters = null)
        {
            DBConn conn = new DBConn();

            conn.command = commandName;
            conn.parameters = parameters;

            return conn.run();
        }
    }

I am pretty sure that there is a better way.

Could anyone help me? Thanks is advance.