Listen to the founders of soul music..... and some of the off spring as well.
Al Green, Temptations, Sly Stone, James Brown, suggesting these as a starting point.
As a suburban white kid growing up in the 60's and into music, that is what I was listening to back in the day..... also in that mix was the Beatles, Stones, Who, Deep Purple, and so many more really great artists and bands from all sides of the musical aisle.
Expose yourself to as many diverse musical influences as possible in the genre you love and most especially ones that you may not like all that well. Include jazz, country, bluegrass, cajun, european, and as many others as you can. You will learn something from them all.
When it comes to songwriting..... (one of my favorite things to do and talk about) there are no rules per say..... there are however, certain "current rules" and suggestions. What is acceptable now may not be in 6 months.
When I set down to write a song I do not start out by saying I will write to this or that formula.... ABABCB or ABCABCDC or BAABAB. I let the song dictate what structure it will be. Keeping in mind that depending on the genre.... certain structures are more conducive to hit songs than others. I simply write what I feel and it will generally take one of the major structures all by itself.
I'm mainly a country writer, although I do dabble in other genre's from time to time. Years ago it was common to start a country song with the chorus, but in today's country that is almost never done. Now, ONE verse followed by pre-chorus or straight to a monster killer hook chorus rule in Nashville. Lots of songs that are hits are simple ABAB song structures. The chorus and hook determine if it's a hit.
The mantra is "don't bore us, get to the chorus" ... that's in Nashville. But I think that would also apply to the pop music world as well.... Many songs have meaningless or of disputable value verses... they are place holders... the real goal is the chorus..... the hook is there and that is the part everyone sings and remembers.
A good idea would be to seek out songwriters in your genre. There are sites and forums online that cater to every musical taste.
I was with TAXI for a time: they cater to film & tv.... they have a great educational aspect and as a visitor to the site you can join in the forum for free. Meet others from ALL genres there. Members can submit to musical opportunities in the film & tv world as well as artist listings. They also do song reviews.
Nashville Songwriters Association: all about writing and education in that line of thought. As a member you get 12 detailed reviews and one on one (1 hr each) sessions with writers who have had hits and careers in the biz. They have an extensive members only library of online videos that feature people in the biz explaining details of all aspects of the business and especially focused on the writing of songs.
Songwriting is not a natural thing for most people. It is a learned skill and as with all skills, you can become much better at it by doing, and by associating with other more skilled writers and learning to do what they do.
Even the biggest and best songwriters, the ones that write the hits.... write an average of 50 songs to one chartable top 10 hit. So get busy writing..... find kindred souls, and learn all you can about the craft and art of writing a good song.