Once you send an agreement over, waiting anxiously for a reply isn’t the best feeling. Before you even think of sending another email, see if you can meet in person to get the document signed. This works better than any online correspondence. If that doesn’t work (especially for a time like now), then try BreezeDoc or DocuSign so you can have the other party sign it electronically and conveniently. Remember, you want to make things as easy for them as possible.