I worked in a lab as a lab tech and developed my own research project that I've been working on for over a year. I'm currently only working part time as I have a full time job. My supervisor recently got a new honours student who's been working on collecting data for the same project and has expanded the project for her thesis. My question is, when our research gets published who should get first author? I developed the project, collected data, created a poster for a conference, and will most likely be involved in the writing process. However, the new student has expanded the research project, is collecting data (more consistently than I am, because I'm only there part time, and will be writing a thesis for her honours. Who should get first author if the project gets published?
There is no general rule on how you determine the order of authors. In some areas (like Mathematics, for example), the order of authors does not imply the relative size of their contributions --- it is typically alphabetical. This strategy has its benefits: for example, we are less likely to include "star" and "virtual" co-authors, because there is no way of distinguishing them from real ones. And of course it simply saves time and helps to maintain good relationships.
In some areas, the contributions of each author are explained at the end of the paper (e.g. "data collection: Dr A, Dr C; statistics: Dr B, Dr C; visualisation of results: Dr A; writing the manuscript: all authors").
If neither of the above helps, the best way to handle author ordering is to discuss it before you start working together. Definitely, by the stage you have your first draft everyone has to agree on this, and no last-minute changes can be done without full and active consensus.