I don’t make enough to merit SEMRush but I really like using HOTH for all my key word research before I create a post title. It’s tools are free for the amount of times I use it in a month. https://www.thehoth.com/
also use the Google suggestions after I type in a topic. I try to make the top few google questions my H2 and H3 titles through out.
I’ve been on an SEO learning hype recently myself, trying to teach myself things beyond the basic SEO tips you see flying around, and I found Debbie’s eBooks on this super helpful. (Referral link, but I actually bought them myself!)
She gets like over 600,000 pageviews a month and a huge percent of that is just organic traffic - which is insane and incredibly motivating.
I also finally invested in a keyword research tool - Keysearch - and it changed the game for me!