For the first question:
1. Once in Microsoft Visual Basic Editor go to View then click Tab Order. You can tell Visual Basic which textboxes would be highlighted first.

For the second question:

If Not IsNumeric(TextBox1.Value) Then 'numeric values
MsgBox("Please enter a numeric value.")
End If

If Not IsDate(TextBox1.Value) Then 'dates
MsgBox("Please enter a valid date.")
End If