I cut my new vinyl flooring too short, causing a gap at one wall. How can I cover it up?
You can use quarter round to extend your baseboards and cover small gaps.
If the gap is really large you can cut a new larger piece of the flooring and line it up with the current floor in order to create a hopefully invisible seam. I think it generally looks better to have two large pieces with a seam instead of one large piece and one small piece.