Enterprises cannot get enough good advice for securing their IT systems, data centers, email accounts, mobile devices and so on. There are so many people offering advice, for one thing. Start with conventional security providers who rely on old-school methods like passwords, “mother’s maiden-name” security questions and so forth; then, there are the medium-age security providers who use tokens, encryption and some new-fangled functions like biometrics (fingerprints, generally) to try and get systems locked down. Newer companies are bringing fresher ideas to the table, such as big data analytics for risk assessment software, honeynets and others. The common denominator: Nobody yet—whether a company or an individual—has completely been able to shut down intruders on an airtight basis. This eWEEK slide show contains some basic, but sometimes overlooked, industry advice from five professionals who know their business. Their suggestions range from checking URLs, to verifying senders, to keeping your browser and operating system up-to-date.