Some tools are essential for decoupage, such as scissors, glue, varnish, cotton swabs, damp rag and various images of all kind of sources. Its also a good idea to have tweezers, craft knife, cutting mat, paint brushes, craft roller, piece of sponge, metal ruler, colored pencils, water soluble pen and decoupage medium. However, there are a number of other items which are nice to have for decoupage but not always necessary:

Paints

Water-based paints are the best to use, including acrylics. If the paint says it says it can be diluted or cleaned in water, then it's water based. Acrylic paints come in various sizes and a large range of colors. Most good craft shops have small bottles, which are ideal if you have a smaller object to paint. It's best to use foam applicators to apply paints as it lays a smoother layer than a brush, which leaves small grooves. For a larger project, you'll need a paintbrush or foam roller.

Felt and Cork

These are useful for finishing off a project and giving it a professional look. Glue either cork or felt to the base. This also prevents scratches on the surface where you display your item. You can use self-adhesive cork or you can simply use craft glue to glue the felt or cork down. When dry cut carefully along the edges. With cork, use a very fine sandpaper to smooth the edges.

Sandpaper

Sandpaper comes in various grades but usually a 300-grit and 400-grit sandpaper should be fine. You night need a coarser grade if you are preparing old painted or varnished wood.

Sponge Applicators

These come in various sizes and are ideal since they don't leave stroke marks. The best ones to use are firm, high-density foam since they last longer. Never use them with paint or varnish that needs to be cleaned with turpentine as this ruins them. Using a foam roller when painting a larger surface gives a slightly textured finish.

Porcelain Medium

Porcelain or ceramic medium can be used as a sealant, glue, and finishing coat. It's a thermo-setting, water-based product cured in the oven. This is the ideal for decorating glazed ceramics, pottery, glass, tiles, tin, or enamel. It forms a hard scratch and heat resistant film. It's expensive, but a little goes a long way. Surfaces need to be dust and grease free. Brushes can be cleaned in soap and water.

Fabric or Textile Medium

Fabric or textile Medium is used as a sealant, glue, and finishing coat. It's water-based and can be used on cotton and cotton mix fabrics. The fabric needs to be washed first to remove sizing. Once applied, it must be dried for a few hours and then heat-sealed by ironing.

Candle Medium

Candle medium is used as a sealant, glue, and finishing coat and is a water-based product. It can be mixed with equal parts of paint to paint the candle before decorating. It tends to be sticky and may need a layer of water-based varnish over it.

Outdoor Medium

Outdoor medium is used as a sealant, glue, and finishing coat. It's used for metal, plastic, terracotta tiles, stone, wood, soap, pottery, glass, hardboard, wall, galvanized metal, and candles. It is slightly waterproof and waxy properties and unsuitable for fabrics.

Gesso

Gesso is used to create a perfectly smooth and blemish-free surface. There are also colored gessoes available. You can apply gesso to wood, bisque, and eggs. A smooth surface may need four to six coats. Lightly dry sand each coat and wipe off dust with a damp sponge. After the last coat, wet sand with superfine sandpaper. The gesso will be gooey but when it dries, the surface is smooth. You can mix paint with the gesso to make your own colored gesso. Gesso makes a difference on wooden boxes with rough routed edges and means that they require fewer coats of varnish. Usually, you need only wipe the gesso on with a piece of cloth and wipe off. This leaves a thin layer.

You can make your own gesso by mixing equal parts of PVA glue and whiting. Whiting can be found at paint stores and sporting supply stores. It's used for marking lines on athletic fields.

Crackle

There are two different types of crackle medium - one is applied between coats of paint and one on top of the finished work. The size and shape of the crackles depends on the sponge you use. The larger the holes in the sponge, the larger the crackles. Sponge on your topcoat thickly and quickly, rotating the sponge as you go. Don't go back over areas you have covered. Crackling will begin immediately, so you can't go back without destroying out the crackles.

When planning your crackling, decide which color is to be the top color and which is to be the crackle. Using contrasting colors gives a more pleasing result. For example, for a red box with white crackles, paint the white first, then crackle medium, then red paint. Leave it to dry for forty-five minutes after applying.

Karen's website has a Step by Step guide on Decoupage. Please visit the site for info on decoupage