Starting issues

Hey all,

I have a 2009 RRS HSE.

It started on Saturday....put my key in the ignition, turned it and nothing for a moment, then it started.

Then it ran fine the rest of the day.

Sunday...it began to start, stopped, then started....nothing more the rest of the day.

Today, go to leave for the office and it did noting when I tried to start it, turned the key off, and tried again and it started right up.

Sitting at my office wondering the next step.

Here is my plan, and I am looking for suggestions...

1- check battery terminals
2- Check for loose engine ground on the bonnet hinge
3- try to find the starter and look for loose wiring connections...

Beyond that?

Thanks for all the advice, and thankfully it is no long er 9 degrees outside to work on her.

Chris