Portal: Still Alive

Only ever enter the Orange portal, after you've obtained control of both of them.

I attempted this achievement (successfully) many times and had it fail to unlock. The game is very picky as to what constitutes not entering the blue portal. Here are the tips I used to unlock the achievement on my actual successful playthrough:

1). It is OK to start from the chapter where you obtain the fully powered device. Playing from the start is not required.
2). Don't take too long going through portals.
3). Never ever stop in the middle of a portal. Never hang in portals.
4). Always jump + crouch through the portals to ensure you pass through them quickly. If you mess up, reload your last save/autosave. THIS JUMP+CROUCH ONE IS IMPORTANT, I CANNOT STRESS THAT ENOUGH.
5). I sent both boxes and plasma pellets through blue portals and was fine. YOU may not pass through a blue portal. Just about anything else can.
6). Grabbing items through portals without entering them yourselves is risky as you have to get quite close to the portal. When done correctly, it's possible to do this without messing up the achievement, but I advise against it. Why make it any harder than it already is?

The bottom line is, this achievement is very picky. You better be damn sure you're doing it right ;)

Just got this first time starting at chapter 4. Its actually far far less intimidating than it sounds, you can get a clean movement into an orange portal and out a blue one about 99% of the time, and event he few times where the transition wasnt as smooth as i would have liked, i played on and got it anyway. I saved at the beginning of chamber 18 which is where it starts to get a bit hairy, from then on its a case of just being mindful of which portal your putting down first, so get into the habit of putting down the blue one where you want to EXIT first, and the orange one wherever else. It wont take very long either, from chamber 10 to 18 was about 2 minutes and from 18 to glados was about 40 mins to an hour. Just keep mindful of your portals and thers no reason not to get this i find, as i said i got it first time in about an hour.

Save often. From Chamber 11 on make sure you enter only the orange portal. On chamber 18 when you come to a seemingly impossible part where you have to you momentum to continuously go upward, shoot the blue portal on the new platform u see and quickly look down to shoot the orange portal below u. Make sure to never stand in between the two portals. When your escaping from the lab, u'll encounter a part where u come to a slab of concrete that u shoot and once u go through the orange portal, u'll be standing between the two of them because the concrete is so low to the ground (u'll no what i mean), just quickly press B to duck and save before hand (or use last save an remember to save before tht part). When u fight GlaDOS, the second eye thing u have to incinerate will be up on these pipes. Shoot the blue portal a bit above it and shoot the orange portal somewhere else and go through the orange one and drop down onto the eye thing. If at any point u feel u accidently went through the blue portal, reload ur saved game. If u beat the game, but didnt get the achievement, u do not have to start completely over or from chamber 11. go back to where u feel u may have messed up and try again.

Just to clarify, something that I didn't know: The achievement pops right after you defeat GLaDOS, NOT when the Is Anyone There? achievement does. It took me a grand total of 5 playthroughs to get this achievement because of that.

Something that should be pointed out, but has been missed so far: make sure you know the game backwards and forward. It makes things a lot easier knowing exactly what you need to do.

This is especially true in chamber 18 when you have to precisely shoot portals when being vertically flung out of portals on increasingly higher platforms.

Personally, I didn't crouch-jump, but I did make sure not to stop when going through portals. I messed up a few times, died a few times, but I always made sure to reload the last auto-save when I did. Luckily I got this on my first try.