SamBC's answer is excellent, I just thought I would add an example of what the historical present does look like so you can spot it in future.
In 1066 William the Conqueror travels to England with his army of Normans and defeats King Harold at Hastings.
Winston Churchill works every day in his bunker office in London's Whitehall, all through the German Blitz.
Historical present sentences tend to be quite straightforward. They are very clearly written in the standard present tense. So, they should be easy to spot. What makes them 'historical' is the context, which will always be to things clearly in the past.
Bonus: Two pieces of advice about the historical present:
- Never use the historical present.
- Really. Never use the historical present.
Professional historians in my experience loathe the historical present, and you will rarely find it in works of history other than 'popular' histories. There is never any particularly good reason why using one of the past or perfect tenses isn't appropriate. Where you do find it is in journalism, TV history shows, and undergraduate essays. There is an argument that the historical present gives "immediacy" to writing when talking of long-past events. I'd argue there are better ways to create that "immediacy" if it is necessary.
Ok - I know being prescriptive with grammar is unfashionable. But if you do use the historical present, I think it's good advice to ask yourself if you really need it.