Please note, Solar Plains requires the server to be as recent as Intel's HASWELL processors, starting at model 4250U.
For clients connecting to a server, this requirement is lower, anything as recent as the Intel Core 2 Quad should be capable of running this game fine, as either singleplayer or client.
Use tabs - any editor can configure a single tab into X amount of spaces.
Keep it simple and modular - if it stops working in one version but works in another; it's entirely replaceable.
If you're struggling with that, write the logic flow into smaller steps on paper first; you'll see how much of a difference it makes.
Use each mod's namespace for functions; you may never know when another item implements something similar.
Try and reuse code whenever possible. Beds is an example that shows that this is possible.