A Few Questions on Druid

[Scorponok]

I'm trying out a Druid for the first time in 5th Ed, and I'm not quite sure about the rules on spells.

Example, I'm a 3rd level Druid I can prepare 4 1st-level spells and 2 2nd-level spells. If I chose Cure Light Wounds as one of my spells, it says I can cast it as a 1st or 2nd level spell, and I don't lose the spell when I cast it. Does that mean that if I prepare that spell, I can cast it spontaneously 4 times that day? (Assuming I haven't cast any spells yet.) The wording is a bit confusing on the class description.

If say, I prepared Cure Light Wounds, Entangle, Healing Word, and Faerie Fire, normally in 3rd Ed, I can only cast one of each spell a day. Does this mean I can now cast 4 Entangles, or 4 Faerie Fires, or must I use a 2nd level slot to cast those once my original Faerie Fire is used up?

[Foodle]

Yes, you're more like a sorcerer of 3.5.

The spells you choose to prepare for the day act as your spells known. You can cast any of them by using a slot of their level or higher as many times a day as you have spell slots.

You could for example, cast faerie fire in a level 1 slot 4 times, then cast it two more times using up your level 2 slots. For a total of 6 times a day, though all your spell slots would be consumed at that point, so you wouldn't be able to cast any more spells until after a long rest.

Some spells are more powerful when cast using a higher level slot too, like cure wounds.
Cast in a level 1 slot it does 1d8+wis mod healing, while when cast with a level 2 slot it does 2d8+wis mod healing.

[Chronos]

You're also only limited in the total number of spells you prepare-- You can divide them up between levels as you choose. So, for instance, a 3rd level druid with a 16 or 17 Wis can prepare 6 spells. Those can be four 1st and two 2nd, like you said, or they could be six 1st, or six 2nd, or anything in between. Though preparing six 2nd is probably a bad idea, because then you wouldn't be able to use any of your first-level slots.

[ChubbyRain]

A good bit of advice for casters is to prepare a low number of spells in levels you don't have a lot of slots and prepare more spells in lower levels.

Diversifying works wonders in this edition. You don't need 5 concentration spells, choose a specific debuff concentration spell for the day and use that. If you have mostly one type of spell then diversify based on saving throw or effect. Heat Metal and Blindness are both good debuffs. One does a bit of damage and gives disadvantage while the other one gives disadvantage and grants advantage to attackers. However since the targets can be a bit different you may see you need to cast one of the spells or the other based on your situation.

Also, don't be afraid to leave the damage to your cantrips if you have other damage dealers in the party. Your cantrips will keep up good enough and the druid spell list is one of the best in the game (Controller).

Though keeping a spell light call lightning around just in case never hurts.