Should I point my domain to my IP or by using reverse DNS?
What is best practice when pointing a domain to my Linode?
Can I just use the IP or should I use reverse DNS for it?
I'd recommend doing both. Adding an A record pointing your domain to your IP is essential for getting it to resolve correctly. As for rDNS, this is a DNS lookup that does the opposite by resolving your IP to your domain name.
For context/reference I'm linking a few sections from our guides that go over setting up your A records and rDNS.