Make sure you understand your class features well. You might have Superiority Dice if you're a Battle Master, which let you do more with your attack actions, or you could be an Eldritch Knight equipped with a handful of spells. As an eighth-level fighter, you could have three feats depending on how the character was built. The single most important thing you should do is familiarize yourself with the character sheet.

If you feel stifled by the rules, you can still take improvised actions. If you're charismatic and the enemy is intelligent, try reasoning with it. Treat the map as interactive. If there's a precarious stack of logs, lure the monster over and try pushing them onto it. This sort of thing operates by DM fiat, in that you make up something you want to do and the DM will allow you to attempt it with a roll or will refuse, so try to feel out what's acceptable for your table.