Trim excess fat from the pork shoulder
Season all sides with salt, pepper, and any desired spices
Optional: sear the pork shoulder in a hot pan until browned
Place sliced onions, garlic, or other aromatics in the slow cooker
Set the pork shoulder on top of the aromatics
Add a small amount of liquid such as broth, water, or barbecue sauce
Cover and cook on low for 8 to 10 hours or on high for 5 to 6 hours
Cook until the pork is very tender and easily shreds with a fork
Remove the pork from the slow cooker
Shred the pork with two forks
Discard excess fat and any large pieces of connective tissue
Mix the shredded pork with the cooking juices or sauce
Serve hot