When constructing buildings for your layout, always use a 3/8" exterior-grade plywood (good one side).  This will prevent warping.  Once your building is finished to the raw stage, make sure you seal it very well with "Prime It" sealer (available from Home Depot), inside and out.

When working with clear silicone, do not attempt to wipe the excess off when wet.  Wait until it dries!  Then remove the excess with an exacto knife.

When building kits such as Pola, substitute the plastic for real glass.  Buy the thinnest glass you can find.  Your buildings will never have "yellow glass" again!  It is much easier to replace the plastic for glass when you are building the kit than to try and do it after the fact.

Cut pieces of 2" blue styrofoam the exact size of the bottom of your building.  You may carve the styrofoam using a soldering iron with a wide tip (use a cement block pattern).  Paint the styrofoam with latex paint in a grey colour.  The styrofoam is waterproof and light in weight, keeping your building dry and off the ground.

Corrugated roofing can be made very easily with "foil oven liners" available anywhere, even grocery stores.  Cut the edges of the liner off and cut strips 6" wide to be used with the paper crimper (available from Michaels).  Put the strips through the crimper.  You can either use them as strips and nail them on the roof with 1/2" common nails or cut then in pieces and nail them to the roof, alternating the seams.  You may antique the roof by using acrylic paints.

When making buildings that have a bottom to them and a removable roof, make sure you drill a breathing hole and the back or side of the building, at the top (about 3" from the top).  Insert a PVC elbow to fit the hole (available at any Home Depot).  You may cover the breathing hole on the outside with a piece of window screening - this will prevent spiders and other such bugs from entering the building through the opening.  When the building is lighted and a bulb produces heat, there should be an opening to let the hot air escape, therefore, the reason for the beathing hole's existence.

Considering the 10' rule, asphalt shingles can be used for roofs.  They do an excellent job of keeping the roofs dry.

When buying figures that have a base, remove the base with your "Dremmel tool."  Drill a hole with the "Dremmel" in the bottom of one of the shoes.  Insert a piece of brass about 1" long and the thickness to fit the hole.  Glue it in place using CA glue.  You may now place your figures on your layout either in the limestone screenings, grass or whatever.  The figures will look a lot more realistic and they won't blow away or be disturbed by those little "critters."

When soldering wires to track, clamp a pair of pliers to the rail (on either side of the soldering point).  The heat will be concentrated in the area between the pliers, not allowing the heat to dissipate along the whole length of the track.