Everyday and every day

Every day means, yep, every day--each and every day. If you ate a bagel for breakfast each day this week, you had a bagel every day.

Everyday means commonplace or normal. Decide to wear your "everyday shoes" and that means you've chosen to wear the shoes you normally wear. That doesn't mean you have to wear them every single day; it just means wearing them is a usual occurrence.

Another example is along and a long: Along means moving in a constant direction or a line, or in the company of others, while a long means of great distance or duration. You wouldn't stand in "along line," but you might stand in a long line for a long time, along with a number of other people.

A couple more examples: a while and awhile, and any way and anyway.

If you're in doubt, read what you write out loud. It's unlikely you'll think "Is there anyway you can help me?" sounds right.