After all these years, and growing up with Windows 3.1, I have seen an entire evolution of computers and software. Touch screens and large resolutions were a pipe dream just 15 years ago. Now it's the norm. Going from a Packard Bell (yes, before HP) that couldn't run 3D Ultra Mini...
Don't always go for the obvious colour. Sometimes, it's better to think first.
Take as much time as you want - there's no limit.
Look for squares on their own, for these are the toughest to clear and should be a priority.