Here is the best way you can protect your vote between now and Monday: check your voter registration with your county Board of Elections and correct any errors. Here's the web page where Cuyahoga County voters can check their info.
Definitely check if you didn't get a mailing from the Board of Elections in September, if you've moved recently, or if you haven't voted in several years.
If you see a mistake or an outdated address, download a registration form here and mail it today or drive it down to the Board of Elections by Monday. (Registration cards must be received by Monday, so if you fill one out this weekend or Monday, I suggest delivering it rather than mailing it.) Cuyahoga's elections office, at E. 30th and Euclid, is open this weekend. Hours and parking info are here.
Doing this protects you from having to vote on a provisional ballot on Election Day and from the possibility that someone could challenge your eligibility to vote before the election.
Early voting has started. Between now and Nov. 4, you can vote on an absentee ballot by mail or at your county Board of Elections. Until Monday, you can register and vote at the same time. Local elections officials are recommending people vote by mail, to avoid possible lines on Election Day -- just be sure to fill out the forms exactly, so your mail-in ballot can't be challenged.