Do not user Klarma-esque services unless it's important. Same with payday loans.
You can use credit cards to build your credit, but your goal should be to pay it off each month. The first month you cannot pay it off in full (sans emergencies), stop using that card until you pay it off.
Bills get paid first. For loans, if possible, try to pay every two weeks to help bring it down faster.
Having a pet is not just getting a buddy, you need to be prepared to take care of them. They cost money and will keep costing money until they pass.
Honestly, check your job's benifits. They hide a lot of stuff sometimes. It was a year into my employment before I realized my job could make monthly payments on student loans. Their payments have saved me in some tight months. 👀
Edit: if you live alone and your place is small (or at least one level) you may want to look into a portable ac, even if you have central air. I take a lot of depression naps so I'm usually in my room, so that's really the only pace I need it. My cat knows where to go when it gets warm and we usually hang out in that room until it gets cooler (of course, if it's bad, I'll turn it on). It's saved me on my electric this year enough to pay for the $160 I got it for (though I was kicking myself because Craigslist had them for cheap).