If you have any Resource Depots still set to more than 1 hauler, you can reduce to 1 to save population. As of 3.2, they will always run at 100% efficiency. Also you can save population by intelligently placing your RDs. Often one RD can serve up to 3 different resources.
Need SP? Try fighting the Boars at Boar Badlands (800sp at rank 65), the Raptors at the Raptor Nest, or even the Spiderwasps at Bigfoot Country (Just attack the ground, you wont see them). The latter produces an infinite supply, although it is a tough grind. You can also attack raiders on other people's bases, just be careful to not kill off resource occupations by accident (See Member Expectations). At level 65, you can get occupations that give well over 1000sp. In addition to doing all of that, ask nicely for Wimp Occupations on the in game chat, and someone will generally try and help you out. There are also a few wimp garrisons out there. This is a garrison filled with just wimps. If you put a plane in front, and units behind, you can rank those units without the wimps being able to use their attacks. You do have to wait 2 hours to get your units back though.
Signup for Tapjoy to get free nanos. Try and watch videos daily in the free nanos section. In main eurpoean countries and US, you can sometimes get several a day. In some countries they seem to be very thin on the ground though. Many guildies have several mega tanks and other nano units, never spending a penny of real money, just through Tapjoy and videos. The best offers give 40+ nanos just for downloading and running an app, although ones this valuable are rare.
Make sure you find the Ancient Rubble. It can boost production of your mines by 25%, and can reach 2 mines at a time in some places.