Check your connections on the starter, and where the battery ground attaches to the engine. Then, try jumping with a wire from the big terminal on the starter (from the battery), to the small terminal (the only other connection)
I would start by using a remove start switch to see if the starter is working, then I look at the stater relay in the relay box under the drives side dash. If the relay is fine, a burnt pin inside the ignition switch could be the issue.
Do not overlook checking all four battery connection points for corrosion or looseness. (The two at the battery, the cable end for the negative at the block and the positive end on the starter).