I'm on my third shelter (gave up and started over twice). At this point, I have four levels full or partially full of rooms, 30+ people, not enough people to staff all the rooms, and my stats keep going into the red -- I'm finding it impossible to keep up.

Did I get too big too fast? Should I make sure every room is occupied with workers before I add another one? I'm trying to fulfill my goals, which makes me have pregnancies going and babies coming all the time. But now I don't have enough electricity for all the rooms, my food is always short, etc. etc.

Advice, please?

I'm willing to bet rapid expansion is the downfall of about 90% of people. As a general rule, only expand as your capping your resources. Build your next building when you're ready, if it's a new building it's going to take power. Check your power to make sure your consistently capping power, then build another building. Or if you're falling a bit short suddenly, shuffle some workers and outfits around or build a new power plant or upgrade your current one to fix your slowly deminishing power supply.

The same goes for dwellers, don't expand your population too quickly. Make space for a few new dwellers, see how it affects your food and water, and adjust. But don't be sitting on 18 dwellers then suddenly make room for 70 and expect to not have some major problems.

Slowly expanding is the key to success.

If you tell me what "capping power" means -- getting it all the way to the top? I will follow your advice for sure.

I'm enjoying the game (I love Fallout anyway), but it's tricky!

If your consistently capping your resources (filling your power, water, and food) without any issues or relying heavily on rushed productions, then you're safe to expand a little. Just take your time with it and keep in mind what each new addition to your vault is going to require in terms of power for buildings or food and water for a larger population. If you expand and your starting to have trouble maintaining your resources, upgrade that resource production to compensate for your recent expansion.

Just take your time and you'll do great.