I am an advocate of the Three Clue Rule. If you want the players to learn a piece of information, always place at least three clues that allow them to get that information. Let's say the player characters should check out an old magic tome: One clue could be an open book on a desk that has the name of the Tome underlined with a note at the margin "Ask if library has a copy"; another one could be a receip from the library for a request to get the tome retrieved from the archive; and a third on two photocopied pages from the tome which fell to the floor when the rest of the copied pages had been stolen. All three hints tell the players we should go to the library and take a look at that tome.

To make the adventure less railroady, also allow the players to visit different locations in any order they want to. Don't force them to go to the library first, but also allow them to investigate other possible leads. Instead of the library, the scene they investigate may also have clues that lead the players to the daughter of the missing scientist and to investigate a freight container in the harbor. Again, place at least three clues that lead to the daughter and at least three that lead to the container.

To make things even more interesting, don't put all nine clues from this example at the initial investigation scene. Put some of the clues at the daughters home and inside the cargo container. For example, when looking at the tome at the library, the scientist may have used a slip of paper with the ID-number of the container as a bookmark and forgot to take it out when he returned the book. And perhaps the scientist forgot his jacket when he last visited the daughter and the reciep from the library is still in the pocket.

I am an advocate of the Three Clue Rule. If you want the players to learn a piece of information, always place at least three clues that allow them to get that information. Let's say the player characters should check out an old magic tome: One clue could be an open book on a desk that has the name of the Tome underlined with a note at the margin "Ask if library has a copy"; another one could be a receip from the library for a request to get the tome retrieved from the archive; and a third on two photocopied pages from the tome which fell to the floor when the rest of the copied pages had been stolen. All three hints tell the players we should go to the library and take a look at that tome.

To make the adventure less railroady, also allow the players to visit different locations in any order they want to. Don't force them to go to the library first, but also allow them to investigate other possible leads. Instead of the library, the scene they investigate may also have clues that lead the players to the daughter of the missing scientist and to investigate a freight container in the harbor. Again, place at least three clues that lead to the daughter and at least three that lead to the container.

To make things even more interesting, don't put all nine clues from this example at the initial investigation scene. Put some of the clues at the daughters home and inside the cargo container. For example, when looking at the tome at the library, the scientist may have used a slip of paper with the ID-number of the container as a bookmark and forgot to take it out when he returned the book. And perhaps the scientist forgot his jacket when he last visited the daughter and the reciep from the library is still in the pocket.