The answer to 'how to unclog a drain without a plumber' is to try using a drain snake or plunger first. These simple tools can often dislodge a clog without requiring professional help. Start by removing any standing water in the sink or tub, then insert the drain snake or plunger and work it up and down to break up the clog.
If the clog persists, you can also try using a baking soda and vinegar solution. Pour a cup of baking soda down the drain, followed by a cup of vinegar. Let it sit for 15 minutes, then flush the drain with hot water. The chemical reaction can help dissolve the blockage. However, if the clog is severe or you're unable to clear it, it's best to call in a professional plumber to avoid further damage to your pipes.