Do the daily heroic story mission, on as high a level as you can, every day. Do at least one public event every day- the first gold tier public event you do each day awards a postmaster package that can contain shards. Use reputation and marks to buy armor from tower vendors, and break the armor down. Use strange coins to buy armor from Xur, and break it down. Use motes of light to buy exotic engrams from Xur, and break the resulting armor down.