To do this you need to generate variables for the fields you wish to keep and then add them back after you make the new record, the code would be similar to this;
Dim field1 as string
Dim field2 as string ... for as many as you need!
field1 = Me.txtBox1
field2 = Me.txtBox2 ... storing the fields
Docmd.GoToRecord,, acNewRec
Me.txtBox1 = field1
Me.txtBox2 = field2 ... restoring the values
Me.txtBox3.SetFocus