I really wanted to like RCT3 but I couldn't get past the RIDICULOUSLY AWFUL interface/menus. That was the only one not made by Chris Sawyer, right? And everyone was picky as hell ...
RCT1+2 had a simple formula.
If you're having trouble keeping guests in the park, I wrote out a full guide on what to do. Yes, I do this shit with every single park. Yes, I've beaten pretty much every campaign (except the boring ones).
Only make single-wide paths, only allow people into the areas you want to (using blocked paths and DO NOT ENTER signs to regulate traffic is a MUST), place info Kiosks in key strategic points, don't bother with food until people start complaining about it, always go for high-excitement rides over high-intensity, monitor your queues & "what they're saying" menu closely to ensure you're changing the right prices, and destroy/rebuild your attractions every 3 years or so. One maintenance man per every 5 attractions, or 1 per every 3 rollercoasters (depending on age). One police officer for every hundred guests. One maintenance man per every 50-100 guests, and special ones designed to only travel high-traffic areas. Always un-tick mowing lawns, unless you want some specifically for mowing lawns. Place benches and First Aid prolifically around ride exits. Place ATMs toward the front of the park and near high-traffic areas. In large parks, always supply transport from one end to the other, preferably free. Always charge $0.10 for bathrooms (no one gets pissed and they pay for their own upkeep costs). Place trees and bushes everywhere to increase happiness. One mascot per major rollercoaster (i.e. very popular) queue, assigned to it. Only tick the development research you care about most (which should almost always be only thrill rides and rollercoasters). Water rides and go-karts are typically VERY popular when new, even at low excitement ratings. Always make DO NOT ENTER signs in front of ride-exit paths, so people don't wander to a ride exit (thus muddling their paths and getting them lost). Double-up the paths only in very high-traffic areas, and only sparsely. Rollercoaster loop-de-loops work best when you are going ONLY JUUUST fast enough to make it through without stopping (slowing on the apex of a loop vastly increases excitement). Always bank curves, if possible (lowers nausea/intensity ratings). If your park's admission and rides are free, gouge people on concession prices. If your park's admission has a price, and your rides cost money, keep the ride prices relatively low (this will keep people in the park longer).
:O man can you tell i played that game constantly