How do you do it?

I made the beginning of a game a few years back that included two villages and two dungeons. It took about two hours, maybe less, to finish everything I'd created. The system data came out to 3 blocks. I know that Scenario data is virtually unlimited, but how do you keep a full-length game inside that 15-block System limit?

Using the pre-made dungeons wisely is a pretty good method to save space.

your blocks are not the limit as you cant actually hit 15 blocks. the real issue is running out of memory which is a much harder threat.

learn how system data is managed then look for a work around:
-having large towns eats up space so cut out anything thats excessive for size.
-know that pasting several town inside a map should be arranged so that the rooms line up as to be square or all in one line.
-use event data when needed to create a map image as a single item can cost 3 system data.
-limit other system data to useful stuff so you dont have a billion spells or too many items and monsters.

i set a benchmark for what my towns maximum size can be and i dont go over this value. for small towns i keep them 2500 to 3000 mem space and keep the rooms to 1000 or 2000. for larger towns i dont go over 5000 for the big ones and try to keep the rooms small. i remove all pointless paths and limit excessive empty walking.

Honestly, if you're going to create any sizeable game, you can't keep your game on a single memory card. Thankfully, RPGM1 allows you to store games on more than one memory card. You can have system data on one card, scenario data on a second card, and Anime Maker data on a third. Plus, RPGM1 has the "Next Scenario" option, which allows you to continue your game on an extra scenario card, much like how many PS1 RPGs did a "Please continue on Disk 2". In fact, you'll find that the majority of finished RPGM1 games here use that feature.

Excellent advice, thanks all. I had no idea that I had even LESS than 15 blocks to deal with... but I'm beginning to understand more fully how System data is used and hopefully this will help me conserve it more. I kind of wanted to make a series of games anyway, so hopefully it'll work out.

Special thanks to Karr for the tip on using Events for objects and lining up rooms. Advanced stuff like that will really help me.

ive been working on my damn game for over 10 years now. at the least you pick up a few tricks. good luck with you game.