Many years ago I decided to stop buying cheap sewing machines from the big box stores. Without doing much research I found a Pfaff dealer. They were in the middle of a sale and I found one that I thought would suit my needs. It isn't terribly fancy but has a huge space for quilting, and more features than I've ever managed to use.
needle, and said "I'm sorry" at least a hundred times. See that pile of lint to the right? Yep, that's what I dug out of the machine.
fresh topstitch needle, and we were ready to get to work on a full day of projects.
I tried to find a single cleaning tutorial that I thought would be helpful but there are just so many out there. Use your search engine of choice to learn more about sewing machine maintenance that matches your machine, and make sure you refer to your owner's manual before adding any lubricant to your machine. Some machines (older mechanical machines with mostly metal parts) can be lubricated with sewing machine oil without a worry of damaging the machine (I oil my long arm with every bobbin change). More modern machines often have oil-free bushings and you'll end up with your machine in the shop if you oil something that doesn't need it, or put oil in the wrong spot.