How do I prevent baking chocolate from getting thick when melting?

It is important when melting chocolate to not let it get too hot. When melting chocolate in the microwave, be sure to stir every 10 seconds. It is possible to add oil to chocolate (15ml oil to 180g melted chocolate), however it will not be suitable for dipping after this but can be used for incorporating into baking (brownies, cakes, cookies).