Sometimes it can be hard to think positively when you don't feel like it. Doing some of these things might help.
Make some hearts and write positive things on them. Put them on a string and hang them up or wrap them around a tree. There's a printable heart template at the bottom of this page.
Make a positivity pot. Decorate it then fill it with lots of positive thoughts. You can keep adding to it in the future. You could also invite your family members to add to it.
Draw at least one person, thing or moment you are grateful for.
Write about or create a comic strip for your perfect day. Where would you go? Who would you meet? What would you see, do and eat? What would the soundtrack be?
Make a list of all the good things about you. This could be what you're good at but also what you're like, for example that you are kind or a good friend.
If you are finding it hard to get along with someone in your family, maybe you could try making a list of all the positive things you can think of about them. It might be hard at first if you have fallen out but keep adding to it and re-reading it.
Draw or create a collage of all your hopes for the future.