--no-brainer: build Information kiosks that sell maps (if you already have them, lower the price or make them free), especially right at the entrance to the park.
--Build fewer paths, and have fewer intersections on them. Make queue lines longer instead (put decorations and have entertainers patrol them to keep people happy while waiting), and use "Do Not Enter" banners (comes with one of the expansions) to create one-way paths.
--if you have elevated paths or bridges, try to build them on raised ground rather than "scaffolding" if you can... sometimes the game can glitch and people fall through the latter, and that can lead to them wandering into undeveloped parts of the park (I've had it happen to both guests and workers).
Forgive him father, for he knows not what ticket he purchases... Yeah I do... see? Zombies! =^.^=