I'm pretty much going to reuse what I said in another thread some days ago:
Us RCT2 players use what we call "workbenches", which are maps with carefully sorted scenery and ride options. The intention of these workbenches is to give the player a ready made selection of what the creator might call good CSO pieces that go well, and that usually produce good results. Simply downloading the entire CSO database of NewElement Designs, one of the premier RCT2/LL parkmaking websites, isn't feasible, so I suggest you download various workbenches in order to add objects to your personal database. Cherry picking all the objects you need is an option, but not one that most people would be keen on when starting out.
There are some great workbenches out there (mostly on NE). Most people would recommend
Pro Tour 2 Bench (2005),
NE Workbench 2017 by Louis!, and
Xtreme97 Workbench 2014, so I'd say those are great starts. I suggest trying them in that specific order, as the first one contains some default NCSO objects as well as a good selection of CSO. This is what most would consider a good introduction to CSO, so to speak. It helps get the hang of some CSO objects, as well as having their previously relied upon NCSO objects. Then, we've got the latest 2017 rendition of the Official NE Workbench, that contains some of the most versatile and widely used objects that guarantee you'll find something in there for you. Definitely, something a lot of users use as their starting point in projects when going full-CSO. Then, at last, we've got a workbench that, while having objects that cater to a very specific group of people, still contains some very respectable object pieces that you'd otherwise miss out on should you try only the other two. Once you've gotten the hang of how good CSO is used, you'll want to manually add your desired pieces to a workbench individually to cater to your specific work each time. For that, I suggest using the
NE Database to look for very specific objects using the search command.
Hope this helps you out.
Currently working on a fictional Italian non-park. Expected release date: Soonâ„¢