When you are sewing you should always use a good quality thread. Poor threads can ravel and break making your clothes last a shorter amount of time. I use Gutermann, but Madeira is also really good. There are other brands that are good that I haven’t used, but I know that those two are easier to find. Gutermann tends to be a little cheaper and go on sale more. Plus, they have lots of colors, so it’s easier to match your thread to your project.
Use good, sharp scissors. Dull scissors can eat your fabric or make it hard to cut. Good scissors are often heavier, but the most important thing is that they are sharp. While this may seem more dangerous, it actually isn’t because you tend to be more careful, and you will feel it sooner if you accidentally cut yourself. Still, you should always be careful and carry your scissors properly, with the point down.