Try using some cores. Cores are a pair or trio or Pokemon that have an offensive or defensive synergy together. Usually, if you snoop around Smogon, you're bound to find cores that are pretty strong in the current metagame. Usually when someone introduces the core, they will also state some potential teammates for that said core, allowing you to (basically) build a complete team from there. It's a very good learning experience for beginners like you and helps you understand the state of the metagame better.