You can (and should, if you’re spending real money) watch some drafts with the set you are drafting (Theros, I assume) and also check out some resources for “best bombs in Theros” and the like.
Also, there ares some simple rules of thumb for drafting/making a limited deck. When drafting, you want to use BREAD. Which is, when drafting, pick (B)ombs first - big, splashy win condition cards. If you don’t see one, go for some (R )emoval, something like Eat to Extinction for example. If neither are on offer, reach for something with a form of (E)vasion, like flying. After that pick up (A)ggro cards, fast and cheap stuff that puts boots on the ground. You’re going for value, so cards that can be re-cast are good, too. Stay away from (D)regs, that’s the shit you get stuck with.
Also, and this trips a lot of players up, put 16-18 lands in your deck, and KEEP IT AT 40. If you are at 41 or 42, it’s NOT good enough. Take out the worst 1 or 2 cards in your deck, to help ensure you get to those bombs and removals when you need.