For metal and cast iron grill grates, coat lightly with a high temperature oil like Canola or Peanut oil – wipe off any excessive oil, install the grates and fire up the grill.  Heat the grill on high and let it burn for ~30 mins.  This will burn all the solvents and impurities off of the heating elements, grill grates, etc.  Note that porcelain grates won’t need a coat of oil, but will benefit from the burn in process to remove any chemicals/impurities that were applied by the manufacturer. 
Try to avoid this if you can, but if you just have to take a peek, remove the steak from the grill and use the tip of a paring knife to make a cut into the center of the steak to see how things are going. Keep in mind that the steak will continue to cook as it rests after being removed from the grill. Cutting into the steak is discouraged because it will release the precious juices that help flavor and tenderize the meat.

Clean the bottom of the grill with a soapy sponge. Once all the chunks are gone, scrub the bottom with a sponge or scouring pad and soapy water to remove any built up grease or grime. Lots of drippings and food scraps tend to build up under the burners of the grill. Pay close attention to this area and clean it as much as possible to avoid corrosion.