I usually play 1v1, so it's weird going to 2's. One of the first things I learned from my 2's partner (he plays 2's but not 1's) is that you have to expand safe if you want to expand at all. Make units on one base and then expand behind those units. There's too much potential for the enemy team to cooperatively mass an all in. In a way you have to start kind of all-in-ish yourself and scout them to determine whether they're attacking. If you can, you have to expand behind enough units to protect yourself.
When I first started SC2 ladder, I only did team games because I didn't want the responsibility of the wins and losses being all me. I was afraid to go it alone. But now that I'm pretty good at 1's, I actually find 2's to be more scary, because in a way there's more responsibility than in 1's. In 1's, you're only making yourself lose if you don't build enough units or don't play good enough. In 2's, there's that much more momentum that can crash against you from the opposing side, and if both you and your teammate don't work in sync, the momentum of the other team working in sync can overwhelm you both, even though one was playing good. So in a way, it's scarier to play 2's for me now because it won't just be me losing. I'll cost my teammate the game too if I play badly.