Format Formulas, Constants, Numbers & Text Cells Differently

I am attempting to write a VBA function that will add textual formatting to each cell that has content. I am just learning VBA; so far, as an example I have

Sub NewSub()
i = 1
j = 1
Do
Cells(i, j) = "'" & Range(i.j).Value & "',"
i = i + 1
Loop Until i = 40
End Sub

but, as I'm sure you'll notice, it does not work. In essence I want to wrap quotes and follow with a comma each cell that contains any content. The actual content test I haven't gotten to yet.