Need to know whether I am going correct or not

Question

I am following way for C#.NET Programs..Keeping in mind that many user will use program at a time

STEP 1 : Generate Unique Id from any table

STEP 2 : Generate transaction in following way

SqlConnection Con = new SqlConnection; Con.BeginTransaction

STEP 3: My sql statements(Insert/Update/Delete)

STEP 4: Commit or Rollback

just need whether I should do any changes or not.Is the above way is good if there are more users using software at a time.