Work
Regarding working at companies, the most important factor is productivity, on work places screen you can see the formula to calculate the productivity, which is dependent on 2 factors energy and how active u are, so daily u have to work 2 times a day to increase activeness count and to increase energy there are different means available, u can have a house (rented/purchased), u can own clothes, u can drink milk or coffee as many times as u want or can drink wine once a day, or u can eat cheese as many times as u want or u can have meal (4 times a day based on system's schedule).
If you buy wine, it is consumed automatically and immediately.
If you buy meal, it is consumed based on system's schedule.
If you buy milk jug, coffee or cheese, u get them under My Inventory screen and consume them when u want to.
If you buy/rent a house, u have to move into the house by clicking on My Real Estate menu from left side of screen.
If you work 2 times a day, consecutively for 3 days, u become eligible for Work bonus, on home screen u can see how much work bonus is approved by the government. You get % of work bonus based on your energy.
Recruits:
Recruits are a good source of income, you can have recuits by 2 means:
1. bring your friends to the game, once a friend joins through your link, s/he remains as your recruit for 3 months and u get income from his/her earnings, after 3 months u have to block that recruit by paying 0.5 euros and that recruit is blocked for 1 month. If you dont have any euros with you, it will be good to put that recruit on sale, for amount in gold, otherwise that recruit will be taken from you, which is 2nd mean of having recruits.
2. When a recruit is not blocked any more that recruit becomes available for recruitment by other players, such recruits can be found under Recruitment menu of Activities menu. You can recruit any of them, which gives u that recruit blocked for 24 hours and also recruitment bonus as defined by government. You can sell that recruit or block her/him by paying 0.5 euro for 1 month.
Another advantage of recruits is that there is a global fund, which on daily basis gives gold to the players who have active recuits with them.

Wars:
Wars is another good source of income, wars occur between countries to occupy regions. One country can attack another country to occupy any region except Capital region.
War can be started by an organization of a country, an Organization can be opened by paying 5 euros and at the moment can have maximum of 10 members.
To participate in a war, u need to have defence or attack weapons based on which side u r fighting for. Your impact in the war is based on number of weapons u have, quality of the weapons and your energy. With every hit in a war, you loosed some energy and 1 hit point of each weapon. You can gain energy by using products or in war u have option to buy energy packs by paying 0.1 to 0.9 euros based your selection. Also reaching a specific damage point (found on war screen) u earn a medal and after having specific numbers of medals of one type u get an army rank, which gives a damage bonus to your weapons. These army ranks are country specific, so if you are a General in USA and later you become citizen of Spain than in Spain you will start your rank journey from Zero and later if you move back to USA, u will be a General

There can be 3 reasons to participate in war as far as I can see:
Money: If you are fighting for money than on war screen at bottom u can see how much gold exist in war fund, if war fund has gold in it, you will get gold against the medal that you secure, otherwise you will only get medal.
You can withdraw by skrill, neteller, paypal, or other options accepted by the reseller in the game