Number one: Dont buy any plastic products or at least try to avoid by reusing it again. It can be applied to many products, for example even before going to groceries take your own bag or used packet, you cant even imagine how could small action make to this world! Since all plastics are worst polluters and hard to renew or excensive to do it. Also when you order a drink, tell you dont need a straw, yeah it may sound strange, but the earth would thank you for that! ;) And nowadays there are many choises like glasses, bottles and straws made of wood or metal.
Number two: Prevent yourself from buyng many unuseful clothes and staff. Be minimalistic, nowadays being trendy is being sustainable and smart, and that is true. Save you money, just buy once quality for bigger price, than cheap clothes many times.
Number three: Avoid using extra water, you probably might think that " nothing really happens if i dont switch tapwater off while shamponing my hair or pouring shower gel". Well, its thought of millard of people in same time! For all that extra water will be spent extra energy, which is harmful to produce even if its renewable :)
Number four: And it would be cheap if you do shopping with full stomach! ;)) It is surprising fact, but so much wastes are just expired or unused food. And if we buy less, they will product less, everything is easy we can decide and make our contribution by choosing carefully!
Number five: Try to not use a lot of energy, for example avoid charging your phone at night while sleeping , its useless and really expensive doing that everyday! this applies to turning night lamps at the coridor or garland, which can bother from falling sleep. Unplugging everything while you are not at home or at night is also good decision to save money and not harm to this planet, which has so less to offer to people.