I have been working on a scifi story since I was in my teens (Back in another Century (Yikes) One of the crazy ideas I had was a kid talking to his Grandfather and asking "You mean zoos used to just have regular animals- not prehistoric creatures? That would be boring!"
When I read Jurassic Park back in 1991, I was really impressed with the idea of getting DNA from insects trapped in amber- Michael Crighton was not the originator of this idea- He had read some articles by a scientist (George Poinar, Jr.) who actually came up with the concept with his wife.
One thing I realized while watching Jurassic Park was that you should NEVER re-create creatures that can FLY- they can then get out and cause havoc. Truthfully, a few bullets from a large "Big Game" gun would take any (Land-based) dinosaur down relatively easily...
Some of the best Dino simulations in a movie before JP was in an obscure movie; The Valley of Gwangi (They Rope an Alosaurus)