I like natural colored gravel. It just seems more peaceful. But that may not be the look you're going for, so it's really more personal preference.
Live plants are awesome. Watch out for sharp edges on plastic plants.
I think I must have tried every food under the face of the sun to get my first betta to eat. The only one he ate was Wardley's pellets. My current betta goes crazy over frozen bloodworms and I alternate between Wardley's pellets, Aqueon pellets, and a powder food that was given to me by a betta breeder. I think it all depends on your fish's taste!
Have fun with your new tank and fish!
Gravel: I actually use the marble kind of substrate. It's easier for me to clean and I love the look! I mix colors and sometimes match them to my plants/decor. It's fun. :)
Fake or Live Plants: Live plants are better but I like the low maintenance fake plants. Silk plants are great because they're safe but all the ones I've had faded on me so I stick to plastic plants now.. I just make sure to sand down any sharp edges. I like the bright colors plastic plants offer.
Food: My favorite pellets- HBH Betta Bites(color enhancing fish food). These pellets are not as large as most of them, so some of my smaller bettas can eat them easily. I've never had a fish turn these down!
For a good snack, I recommend Hikari freeze dried blood worms. My fish looooooove them. Seriously, then get excited when they see the container lol They know. :P
Atlantis - Opaque/Blue Crowntail Male
Captain Bubblesworth - Turquoise/Lavendar Crowntail Male
Amazon - Black Orchid Crowntail Male
Rousseau - Red/White Butterfly Veiltail Male
Senor Fiesta - Mustard Gas Crowntail Male
Naevia - Pastel Veiltail Female
Isis - Marble-ish Deltatail Male
Fiona - Cambodian Veitail Female
Amelia - Blue Veiltail Female
Sophia - Mustard Gas Veiltail Female
Delilah - Marble Veiltail Female