How do I mend clothes without going to a tailor?

It depends on the type of hole or tear. For simple stuff like a loose button, you just need to learn basic stitching - there are tons of YouTube tutorials that show you stitch by stitch. If the tear is small and you want something quick, fabric adhesive works well in some cases, just run an iron over it. Now if it's a bigger tear or you need something more durable, it's worth spending a few euros on a sewing kit and practicing a bit - after that it becomes routine, and after fixing a few pieces you'll be mending everything without any hassle.

don't fall for thinking you need a bunch of stuff: a needle, thread and patience solve 90% of the problems. the thing is to practice the basic stitch (that simple up-and-down one) and then you can tackle any tear, because honestly most of them don't need to be perfect, just functional.

The trick most people don't think about is using thread that matches the fabric color - it seems like a silly detail, but it makes all the difference. If you sew black thread on blue fabric, it'll show right away even if your stitching is perfect. Go to a fabric store and ask for a bit of thread that matches - it costs almost nothing.

After that, the technique is really straightforward: for a straight tear, the most practical stitch is just the basic one, up and down alternating, close together. If the clothes are loose-fitting and drape well, you won't even notice it. The important thing is not to give up - the first time it'll look bad, the second time less so, by the fifth time it's decent. It also helps a lot to stretch the fabric out on a flat surface (like a table with a towel on it) instead of trying to sew while holding the piece in your hand.

For bigger tears or in areas that get stress (like the seam on pants), that gets more complicated and it might actually be worth going to a tailor. But for small holes, buttons, and simple tears, with patience and the right thread you can manage it.

I usually use fabric adhesive tape for emergency situations - the kind you find in sewing stores or online - and it works well for small tears or holes that need a quick fix without a needle. Now, if it's something that needs to last, the best investment is a basic kit: needles in various sizes, a spool of white thread, one of black, and maybe one in the color of whatever fabric you use most (like blue or beige). What nobody really talks about is using a reinforcement patch behind the tear - you stitch around it and it holds up way better, especially on pants or backpacks that get heavy use.