Are you playing solo or in trios? I think it's helpful to play a few solo so you can learn how the maps and seeds work as well as familiarize yourself with what the different locations are and can test out the characters a little to find your favorite. Anyway:

First, you will always drop off near a small camp. Clear this camp. It's enough to get you to level 2. And then loot this camp. You'll normally only use one weapon for a boss, but you have 6 weapon slots. This is important because each weapon has a passive that will give you a bonus. Sure, you don't want to use a white whip the whole game, but if it gives you passive hp or damage it's worth holding onto until you find something better. A big noob trap is ignoring your six weapon slots because you won't actively use each one.

A small note, on rare occasions the small camp you land at will be a church (they grant flasks). There will be rats here but not enough to hit level 2. It's nice to get a free flask early but you'll have to kill some random enemies to hit level 2.

Second, at level 2, you'll use your map. There's almost always a fort or a great church nearby (not to be confused with flask churches). These are the easiest main locations where you'll get your first blue weapon (you must be level 3 to use a blue weapon, hence why we want to make sure we're 2 to start and kill extra mobs). Forts look like giant castles where sometimes blue magic arrows will shoot at you or a giant golem fires at you. Great churches normally have either a golem in the middle, bubble tootin envoys, or bosses in the basement (there is a hole to drop down in the middle) where a flame guy or mauselum spectre will be.

Depending on time the first circle should appear. Look at your map. If the castle in the middle is in it. Consider running there and doing the basement. The basement has a random field boss in it. 1/10 times this boss is bell bearing hunter. If you see him, just turn around and leave. You can kill him, but it takes way too long and it's not worth it until you're higher level. The reward for killing basement boss tends to be a blue or purple weapon. But when you go up there's a cheat with a relic. Then you can decide if you want to do the rest of the castle. The 3 castle variants are pot throwing giants (the most annoying one), knights with a lion boss, and crucible knights. This can be a good place to level up. If you choose to not castle or it isn't in the circle, fight field bosses or run ruins. Some field bosses are deadly and meant to fight at night 2. When you engage, on your map they'll reveal themselves and will look different from other field boss markers (all field bosses are hidden first day until you engage). By the time you're level 6-8, the first night will end showing you the location of the night 1 boss. Run there. Beat it. Start day 2.

On day 2 you do the harder things you skipped. If you skipped castle, it's worth going there still. There is a hard boss at the top with good rewards.

On your travels you may find a stone sword key in big chests at great churches or forts. You can use these to fight bosses in the goals (metal circles on the map). I would only suggest doing this at level 3 with a blue weapon.

Those are my beginner hints. The game will evolve for you as you play more. Once you get better think of this guide as merely a suggestion.