There were going to be three points but I see you've charged the battery...so two things:
Your solenoid may be duff - turn the key and listen for a click as it engages; if not, try a substitute, or make sure your ignition key is still connected, no wires have been pulled off, and that it works as it should. Follow the wires from key to solenoid and make sure they're connected at both ends. If you were working in the footwell I suspect you've pulled a wire out of something, if your key is down by the steering column.
You can also bypass the solenoid with a jumplead or the like straight from the battery to the starter terminal - make sure the car is out of gear - and if the starter spins then that's the fault.
If the started doesn't turn, or is weak, then it's an earth problem or the starter itself on the way out.