Solving a timeout error for SQL query

I am getting this error:

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

I know there are already guides out there to help solve this but they are not working for me. What am I missing or where should I add the code to these SQL statements in my C# program:

String sql = project1.Properties.Resources.myQueryData;

SqlDataAdapter sqlClearQuestDefects = new SqlDataAdapter(sql,
    "Data Source=ab;Initial Catalog=ac;User ID=ad; Password =aa");

DataSet lPlanViewData = new DataSet();
sqlClearQuestDefects.Fill(lPlanViewData, "PlanViewData");

I am getting the timeout error at this line:

SqlDataAdapter sqlClearQuestDefects = new SqlDataAdapter(sql, 
    "Data Source=ab;Initial Catalog=ac;User ID=ad; Password =aa");