Working Code: Can it be optimized?

Hey all. The code I have here works for my program 100%. The issue I have though, is that it runs a bit slower than I'd like. Are there some lines of code I could combine into one line to optimize the code?

If (ActiveCell.Offset(0, 3).Value <> "X") Then
If (Range("A1").Offset(SADOffsetCount, 3).Value <> "X") Then
Range("A1").Offset(SADOffsetCount, 0).Select
Range(ActiveCell, ActiveCell.Offset(0, 2)).Select
Selection.Copy
ActiveCell.Offset(0, 3).Value = "X"
Worksheets("Duplicate_Scan").Activate
Range("A1").Offset(SADInputCount, 0).Select
Selection.Offset(0, 3).Value = SADOffsetCount + 1
ActiveSheet.Paste
SADInputCount = SADInputCount + 1
Worksheets("People_Data").Activate
Range("A2").Offset(SADLineCheck, 0).Select
End If
Range(ActiveCell, ActiveCell.Offset(0, 2)).Select
Selection.Copy
ActiveCell.Offset(0, 3).Value = "X"
Worksheets("Duplicate_Scan").Activate
Range("A1").Offset(SADInputCount, 0).Select
Selection.Offset(0, 3).Value = SADLineCheck + 2
ActiveSheet.Paste
SADInputCount = SADInputCount + 1
Worksheets("People_Data").Activate
End If

I'm eyeing the copy/paste lines in particular, as well as having to select a specific single cell before expanding it to multiple cells.