I make a gingerbread house every year and my top tips would be:

Find a recipe, with dimensions for the templates, in a book at the library or on t'internet (that's the easy bit). To give you an idea of quantities, the recipe I use requires three egg yolks, which is useful because I then have three egg whites for making the royal icing.

• Make templates out of card. Cereal boxes are good because you can use the shiny side against the dough, which will stick to the plain side. If you think you are going to do this for several years, cover the templates with sticky-backed plastic to make them wipe clean. I've only just got around to making myself a wipe-clean set, 20 years after my first gingerbread house ...
  
• The dough will be sticky because it's sugary. So roll it out between two pieces of greaseproof paper. The thinner you roll it, the harder it will be when baked, which improves its resistance to being squished by children applying sweets; but the house itself is in my view easier to assemble and more stable if you roll it out thicker - say half a centimetre - plus nicer to eat. The chances are high all the pieces will be different thicknesses anyway, which is part of the charm of a home-made gingerbread house.
• When you start to cut the pieces, if you find the cardboard templates are sticking to the dough, put greaseproof between the dough and the template, and mark around the template with a blunt knife. If you're careful, you won't cut the greaseproof, just crease it, but it will leave enough of a mark underneath to show you the shape to cut.
  
• You can also cut the dough using a ruler and knife and not bother with templates - which is what I did the first time. The only trickier bit doing it this way is positioning the windows.
  
• When you cut out the windows and door, lift the pieces carefully out of the holes. The door you will use as a door, the windows can be cut in half to make shutters.
  
• You will need baking sheets lined with greaseproof or parchment for baking. You can keep re-using the paper.
  
• You will be baking two sides, two ends, two roof pieces, and bits for chimney/doors/shutters - these last are small bits that you can fit onto a baking sheet wherever there's space, but unless you have a very large oven and very large baking sheets you probably won't be able to bake all the pieces at once. Each piece of gingerbread takes about 10 minutes to cook, and then you need to leave it on the sheet until it's cooled so that it's hardened off a bit before you lift it onto a cooling rack. (You may need extra cooling racks, I have three). It's possible to roll out and cut one piece while the previous one is in the oven and the one before that is cooling, so you get a production line going. You need to be free from interruptions and distractions to do this.
• Let all the gingerbread cool off and harden off overnight. The next evening, mix up some royal icing (don't add glycerine at this stage, you want it to go rock hard when it dries because it's holding the whole thing together). Use lots of royal icing to glue the sides to whatever base you're using (you may need to buy a large one), to glue the sides to each other, and to glue the roof in place. Don't worry if the edges look messy, you're sorting that out tomorrow evening. Find LOTS of DVDs and stack these around the outside of the house to hold the sides up, and the roof in place, while it dries. Glue the chimney pieces together but don't fix them in position and don't fix the shutters/door in place. Leave overnight well away from pets and early-rising small children (top of the fridge, another tidying up job, sigh).
• The next evening, glue the door/shutters in place. Glue the chimney in position. Add some glycerine to the royal icing (which of course you covered and left in a cool place overnight) and beat well.
• Use the icing with a star or shell nozzle to pipe along all the joins and all around the base, covering up the mess you made yesterday and making it look fantastically professional. Go mad on this bit, it makes it look super-impressive (one year I made lattice windows but the icing needs to be exactly the right consistency for this to work). Let the whole thing dry off overnight.
  
• Divide lots of little sweets (jelly tots, smarties and dolly mixtures are good) among bowls sufficient for the children decorating the cake. Divide the icing into bowls. You can add a teaspoon in the hope that the children will use this, rather than their fingers, to apply the icing. Agree with the children who is applying sweets to which part of the house. (Our split is 2 x side and end, and one person does the roof, and they have some weird system I don't understand for rotating who gets what (including the end with the door) each year). If you sort all of this out before you start there will be far fewer arguments - possibly even none.
  
• Wash hands.
• Make sure the children don't press too hard when applying the sweets, but otherwise let them get on with it, reminding them not to lick their fingers!
  
• It is possible to assemble the gingerbread house *and* do the piping *and* decorate it with sweets all in one day. But you *must* bake the gingerbread itself in advance, and you really won't have much time for anything else if you do it all in one day, which is why I spread it over several evenings (which is better structurally anyway). You can also make the dough, cut it out, and freeze the uncooked pieces, which, if you do it far enough in advance (ideally three weeks ago) spreads the effort a bit.
• I really wouldn't involve the children before the sweetie stage. Quite apart from anything else, the language can get quite fruity during the assembly stage. And if you lose concentration while you're baking, it burns really quickly, and you won't have enough dough to make a replacement section. Plus, children aren't very good at waiting, and there's an awful lot of waiting in making a gingerbread house.
  
• In our house we have developed several traditions around the gingerbread house:


The sweetie-sticking is done on Christmas Eve afternoon, when all the deliveries are done, I'm baking the mince pies, we've got Norad Tracks Santa up on the laptop, and there's a pleasant sense of anticipation in the house.


Anybody who visits while we're doing this is invited to join in.


The gingerbread house remains uneaten throughout Christmas, so that all that effort gets lots of admiration.


• The children smash up the gingerbread house using rolling pins, meat mallets etc (each child chooses their own weapon) on New Year's Day (our best friends usually bring their children over to join in with this, or we stick the gingerbread house in the boot and take it over to them - it travels reasonably well.)
• Nobody actually eats it. I put all the bits in tubs and take them into the office. But we've been doing it so long that it wouldn't be Christmas without the gingerbread house.