If there's only one thing you do to improve yourself, make it this. When people genuinely value and respect themselves, it's obvious to everyone around them. These people may not all be bubbly and effervescent, but they all exude a sense of self-worth and confidence that makes it obvious that they don't consider themselves losers. Start by thinking of all of the good, valuable things about yourself — things you're good at, ways you enjoy yourself, and so on. Knowing that you have your own unique strengths and talents makes it so much easier to love yourself and so much harder to pay any attention to people who may try to put you down. If you're feeling down and you're having trouble finding value in yourself, try the following exercise. Take a piece of paper and draw a vertical line down the middle. At the top of one side, write "pros", and at the top of the other, write "cons". Begin to write your positive and negative attributes in the appropriate columns. For each "con" you write, try to write two "pros". When you've filled your "pros" column, stop and review what you've written down. Your positive qualities should dwarf your negative ones. People who spend time doing what they love have an easier time loving themselves. The fun and self-satisfaction you get from indulging your hobbies and interests is great for building confidence and increasing your sense of self-worth.  If you're not already doing so, try to spend a little time every day or week doing something positive and fun that you love. If you can do your hobbies with other people, even better — your friends can take the entertainment level of your hobbies from "fun" to "let's do this again as soon as we can".  This advice is especially true if your work or school situation isn't ideal. It can be tricky to find a new job that you love or get a new group of friends at school, but it's not very hard, for instance, to spend a little time practicing piano every evening if you love music. Try to tend towards skill-based activities that you can improve...

TL;DR in Indonesian:
Hargai diri Anda. Curahkan waktu untuk hobi dan minat Anda. Terus aktif secara fisik. Berusaha keras di pekerjaan atau sekolah. Menjadi makhluk sosial yang bertanggung jawab. Rencanakan masa depan Anda. Kelilingi diri Anda dengan orang-orang yang baik. Jangan dengarkan para pembenci.