Well the first thing you need to build the castle to defend you village. I would suggest using a lot of great towers basically everywhere becuase they can take a lot of hits. Even though it will take you a long time to make the castle and countless days to make. I would suggest making something like this.
Now if you are asking why i have used some moats it is becuase my archers are max level and moats slow down troops enough for my archers to kill them. I also have a path going through that castle where my ballistas can just kill everything. All in all a good village. Now the best way to defend during the war is the first excom your enemies so they can not monk them selfs. Don't jst do one village do all of them. Then you want to interdict your self. This will allow you to attack them but they can't attack you. Sometimes you will have to take some hits that is what the base I showed you is for. it will sustain about 6 full armies worth before getting taken.
Hi if you are new to stronghold and you have some of the essentials researched then I advise you to reasearch castlisation. This will unlock the Things you need for a good low level castle. This is what I would expect to see from a low level.
It is good for holding off the ai which is really all you are going to get attack by unless you P***ed off the wrong person.
The first thing I would advise to to make a faction with some friends or join a faction. This tells other players that you have friends that will stick up for you in your time of need. for example if you look at my faction
This is the main reason I have not been razed yet. Anyways if you have anymore questions I am free to answer them in my PMs.