This is for absolute beginners (first 2 weeks), I am putting in a few things that really would have helped if I had known them:

Depending on your world you will have a certain period of days in which you can't be attacked. This guide is based on a five day safe period, but assuming that the world isn't too old, this should still be okay. Use it well, I advise you upgrade your timber camp to lvl 7, your clay pit to lvl 6, and your iron mine to lvl 5.

Depending on how often you can get to your computer will decide how much you must upgrade your warehouse right now. A lvl 5 is good if you can get onto tribewars twice a day, otherwise make it a bit higher, maybe even 10 if you can get the resources. Try to upgrade the warehouse about once every 1-2 days.

Then, upgrade your village headquaters to lvl 3-5 or so, so you can build a barracks and a smithy. (Barracks needs lvl 3, smithy needs lvl 5)

If you have all that, you can build a barracks, because now is the time to start worrying. You need a few spearmen and, if you can get it, a smithy, a few swordsman, about 10-20 of each.

Upgrade your wall to whatever you want, just don't forget to keep a bit of resources to upgrade your mines and things. It's a bit of a short term vs long term thing. A wall of about lvl 2-3 should be alright for now.

It is very important to join a tribe. The tribe probably won't send you an invitation on their own, so go to map. Look for a tribe that is strong but just as importantly has players around you. There is no point in joining a tribe if all it's members are too far away to support you. Click on a village that is in this tribe, then find the tribe leader or recruiter (if they hav one) and message him to invite you to join. An icon of an envelope will appear on your mail tab (top right corner) if they have sent you a reply.

Otherwise, if you can get to your computer frequently and don't mind doing a lot of work running a tribe, you can make your own. This is not for everyone though, so make sure you are up to it. I would only recommend making a tribe if you have some experience.

If you are paranoid you can always upgrade your hiding place, just don't concentrate too much on it, lvl 3 (what you start out at) will be fine for now, trust me. Generally, there is no point in having a high level hiding place. If you are being farmed you don't have much of a chance on the world and should restart if you think you're getting the hang of it. However, if you are being farmed and wish to annoy the attacker, feel free to build you're hiding place to lvl10.

And, that's about it for a good start...