Join the new world

eRep is a casual game. If you're interested in getting involved politically it can be more engaging, but in general it is quite slow. In terms of progression, the goal is to go from having your actions cash-bound to health-bound. At the beginning you are cash-bound (you don't have the money to afford food and weapons).

The rules for eRepublik change all the time and I think we're on the verge of a big change. That said, currently the best way to generate income at the beginning is to:
0) Do missions; check the wiki for details on the rewards for each mission
1) Save your wages, don't fight unless it helps with a mission
2) Work every day: 30 days in a row gets you a hardworker medal (worth 5G, or 6000CAD on the currency market)
3) Build Oil Rigs and Fruit Orchards
4) Sell everything you produce (food and grain) that you don't consume working.

Oil Rigs and Fruit Orchards are relatively cheap (2000CAD + 1000CAD for the land) and allow you to produce raw materials by working in your own company (right now you can produce 112 raw materials by working in either a Fruit Orchard or an Oil Rig). The cost of working is the cost of 10 health (~2.5CAD) and the raw materials you produce sell for ~25CAD; therefore, the ROI on either property (days/shifts to recoup investment) is ~120. Once you have 10-15 oil rigs/fruit orchards, it makes sense to transition to Cattle Farms and Saltpeter Mines: they have a slightly longer ROI but allow you to produce substantially more raw materials for the same amount of health.

When choosing between Fruit Orchards and Oil Rigs, consider:
0) The raw material requirements of your Food Factory; you want to produce enough that you don't need to buy raw materials.
1) Typically weapon raw materials sell for more than food raw materials.
2) Production is determined by the regional bonus of your country, and Canada typically has a higher food bonus than a weapon bonus (however they are currently tied at 3 regions each).

At the beginning you are given a Food Factory and encouraged to build a Weapons Factory in a later missions. The weapons factory costs 10G (~13000CAD) and generates about the same income as a Saltpeter Mine; it's probably not worth it unless you are working so much that the associated town hall upgrade makes sense. As always, when buying/building companies, check the market (Market->Companies For Sale).

Finally, this article applies only to those not buying gold. If you are buying gold, then you are immediately health bound and don't need to worry about generating in-game income (just real life income).