Allow me to write you a list of things that won't work well on Mars. A super soaker water rifle: There is less than a 50th of Earth's air pressure on Mars, which means water will evaporate away, even while inside the super soaker. Nike Air Pumps. With an atmosphere less than 1/50th that of Earth's, you won't be pumbing anything. Matches. No oxygen Kyte. Not enough atmosphere Oxygen. Okay..this would solve all the problems above..if you bring a whooooooole lot of it. Have a nice trip!!! =}
Any group of people that go to Mars will live in perminant buildings. Creating a sustainable atmosphere inside sealed buildings wouldn't that difficult. You can use a green house for that effect. This would also be your source of food. You can use multiple green houses, eventually, to release more and more oxygen into the Martian atmosphere. One of the most critical things we would need for mass colonization is to warm up Mars but warning atmospheres is something we're pretty good at.
For a while, they would need to be vegetarians. Bringing animals such as cows would cost enormous amounts of space in the ship(s) going to Mars. Whatever animals you bring with you, you also have to bring even more food and water for. You also have to create an even larger living space on Mars and bring even more building materials. It would be to impractical