Summarize this article in one sentence.
Especially when you're a beginner you can screw up with cutting the glass or grinding it down. This will leave you with gaps between your pieces. Compensate for these inaccuracies by filling the gaps between your glass pieces with copper solder. Solder as you would normally. There are lots of things that can go wrong with scoring your glass and most of these have to do with how you're standing, how much pressure you're using, and what sort of a cutter you're using. Make sure that you're standing for long scores. This will give you better reach by utilizing your shoulder and upper body in the scoring motion. For small scores, make sure that you stay seated so you can concentrate on following the marker score line. Use the right glass cutter. You do not want to use a five dollar cheap glass cutter as it doesn't cut clear, thin glass very well and it certainly won't cut much harder art glass. Get one that it has a carbide head, because the oil lubrication is very useful. Make sure that you apply even pressure throughout your scoring. Remember you should hear a zipping sound as you score. Also good to remember: Opalescent glass requires more pressure, Cathedral glass requires less pressure. Like scoring, soldering your glass can yield some problems if you're not doing it correctly. Make sure that the heat is correct, that the tip of the soldering iron is the right size for the project, and that the flux you're using is good for higher temperatures. Using the wrong kind of flux can lead to charring, called 'black tip syndrome.' When this happens it means that the tip of the soldering iron turns black and re-tinning becomes impossible. Use the right size soldering iron tip. Make sure that you know what the width of the glass you're working with is and have the tip and the copper spaced accordingly.
Deal with gaps between your pieces. Avoid problems with scoring your glass. Deal with problems while soldering.