Here are a few of the things I gleaned from my experience in trance-journeying into Swartalfheim:
Galdr can be helpful when dealing with the Dwarves or traveling to (or within) their realm; they too use Galdr-chants for purposes similar to ours. I do wonder, though, that if the Dwarves have knowledge of runes that we in Midgard do not (as is hinted at in Sigdrifumal), that they may have Galdr unique to their realm as well. Could an enterprising traveler learn of these, and if so would they even hold any power in the middle-garth?
The Dwarves appear to have Might, not only with metals and stones, but also with healing herbs. Whether it is a skill in coaxing them to grow from fertile earth, or skill in their preparation and use, I don’t know. Since the Dwarves hold power over the deep earth and the materials within it, it makes sense that some of them at least would have knowledge of matters involving the surface-earth, such as gardening.
Amethyst quartz and black tourmaline may be of some assistance in accessing their realm, but further study on this matter is needed.
Last but not least: Be polite! The Dwarves are formal and cautious, and you don’t know all the rules.