Stick to the green grass areas with the beech trees at first. Difficulty scales by biome. Forest (fir and pine trees) is second, swamp is third (difficult to get used to), mountain is fourth, plains with the brown grass is fifth. Don't go out of order until you know what you are doing.

You always spawn in the meadows, but mountains or forest might be close by.

Dandelions are used in a few recipes but aren't food.

You get the cold message anywhere at night, but it only means that your stamina regens slower, which makes it harder to run and fight. It's better to stay inside at night anyway because harder monsters can spawn.