Most Bitcoin thefts occurs due to user careless and ignorance, like not using two-factor authentication and sharing email and password across questionable websites. The risk of theft can be easily reduced by taking the basic security measurements which you should follow in any case when you are dealing with Internet.
Here are some things you should include in your presentation
Don't use questionable Bitcoin services or exchanges (see: Mt.Gox) - if you are unsure ask the Bitcoin community about the integrity of the service. Any "free bitcoins" sites are definitely no go.
Always enable two-factor authentication when using Bitcoin services (exchanges, web wallets)
Keep most of your Bitcoins in a cold wallet or vault service which is not directly connected to Internet
Don't install unnecessary software on the computer you use to handle Bitcoins. Especially don't install software from download sites (even legit ones) or from Bittorrent. Always download software directly from the site of the author.
Don't install unnecessary browser extensions
Don't use the same computer to surf on questionable sites (adult entertainment, illegal software, tor) - you usually get malware infection from sites like this
Keep your computer software up-to-date
Don't click phishing links
To reduce the risk of malware, use safer operating systems like OSX or Linux instead of Microsoft Windows. Please note that this only lowers the malware risk, it doesn't guarantee immunity if you don't follow the other advices mentioned here.
More information about Bitcoin end user threats can be found in this question.