There is really no mystery, nor needing expensive ingredients to get good skin contacts. Remember, human body is essentially a saline bag (just water, salt, and tissues), so most saline solution or gel are all very compatible with it.
I. Sweat: (your own natural conductive solution) If you sweat easily or sweat a lot, you already have your conductive solution in place, and it will replenish itself automatically. If you don't sweat easily or normally, you can start doing some light exercise right now, to get the sweating started. Just a little bit is quite enough. Now if you do need a little extra help to get enough sweat, try saliva (another natural conductive solution). If that's too personal and repulsive for you, below is a more formal solution.
II. Conductive solution: (artificial sweat) Just drop a tiny pinch (less than 0.5g) of table salt (NaCl) into a little water (5~10cc), stir with your finger a bit, apply a drop of the solution using the finger to the electrodes and to the skin locations. You are ready to go, and the rest of the conductive solution should last quite many days. Now if you prefer to turn the ordinary into something more elaborate, here it is:
III. Conductive gel: Just mix a tiny pinch of table salt, into your favorite gel (aloe vera gel is nice), and you are done (see link below). A little (5~10cc) can go a long way. It's really not that critical if the salt amount is a bit more or a bit less. If you like, adding a few drops of shampoo can help with oily skins too. The conductive gel is very easy to clean up, just wash off with water.
Of course, you can also purchase commercial products with good adhesive property, but search the web for good prices first. The price may vary drastically, from brand to brand, and even for the same name brand product. (for example, Tensive Conductive Adhesive 50g tube can cost from $4.99 to $25; Spectra 360 Electrode Gel 250g tube can cost from $3.19 to $9.00.) http://www.ehow.com/how_8637886_diy-electrode-gel.html http://openeeg.sourceforge.net/doc/hw/electrodes/passive/