Do not pay a collection agency in full just yet. Paying off an old collection sometimes actually hurts your score because it updates the “last activity” date. Talk to a professional or do research first. It’s weird, but true.
Do not obsess over your score every single day. Checking it too often can tempt you into making panic moves. Check it once a month, like you’d pet a cat—gently, and with respect.
Do not believe anyone who promises instant 100-point jumps for a fee. They’re selling snake oil. The only reliable shortcuts are the ones we just talked about.