I will be finishing my game programming and development degree soon, and I would like to start developing my own game prototypes to build a portfolio. I was thinking of trying to make three separate games: a mobile game, a virtual reality game, and a console/PC game. I already have a general idea on what types of games I would like to create for each, but I'm not sure if there is a certain order I should follow while coding each of them.

If starting a full game from scratch, which aspects of the game should be coded first or very early on and what aspects should be left for near the end of development?

Start on a PC, it's the easiest platform to develop for.
If only because it's the easiest to test and debug.
Aside from that, it's the most versatile platform of the three.

It sounds like this is your first project, so make sure you start with something easy:

Connect 4 / Pong / Flappy bird

Byaaah31 said:
I was thinking of trying to make three separate games: a mobile game, a virtual reality game, and a console/PC game.

Better to make a solo game and a game as part of a team. Then worry about what platform to make your third game on.

Three games, even if small, will take several years to develop. How will you pay the rent while doing that?

There's a talented artist/gameplay programmer with previous experience and the resources to pay a few people to help out a little bit, running a devlog for his game Arcadian Rift on YouTube, he's about a year in, and the game isn't done yet. To get a feel for what one motivated, talented person with some pre-existing resources can do in a year, you might want to watch through it:

If i had to start a new game, i will basically code it in Unreal. The best effective engine so far.