Just to reiterate, labs (most new dogs) are very much 'hard work'. He/she won't just be a possesion of the family, but *must* be taken on as a family member him/herself.
The first year (or what feels like it, but probably only first 6 months) are quite tough, as dog and human learn how to deal with each other. Be prepared for frustration, and be committed for the big undertaking of a new family member. There probably will be some shredded plants and oopsies in the house. (Get the right cleaning aids from good pet shop before hand).
I'd suggest searching for a good trainer before hand, to be ready as soon as puppy is finally found. The first few weeks, between 8 and 15 weeks, are crucial in a dog's training. This is the best time to learn the basic and most used commands, like 'sit', 'stay', etc. But more than that, to be socialised and learn good behaviour in household. As said before, daily off-lead exercise is very much of utmost importance. Socialisation with other dogs also very nb. Socialisation can be lost, and must be a weekly endeavour, at the least. It is good for them to see as many things as possible early on, to avoid them being frightened (aggressive) when something 'new' comes around. That's why it is good for them to be off-lead at a dog park, where they see all different kinds of people (fat, thin, tall, short, different races, different clothing, different ages) and dogs.
Puppy's love to chew, and older dogs as well. Get lots if treats from good pet shop - this will provide a lot of relief for an anxious dog and aching gums, and also some relief for the humans who want a bit of a break. It is something that keeps the dog busy.
It is very important for dog and human to bond to each other. The dog should be kept close to humans as much as possible in the beginning. It is strange, but the 'bonding' doesn't just happen from dog to human, but you actually start having an enduring 'bonding' experience as well.
Be sure to finalise big decisions with other family members before hand. Will dog stay in or out of house? If in, what times of day, sleeping arrangement? All that stuff.
Teach the dog to potty outside as soon as possible. If inside the house, keep an ever watchful eye on the puppy for when it readies to pee or poo (a particular stance is adopted). React within one second to pick the dog up (which usually stops the no 1 and 2'ing) and put outside on grass. Give heaps of praise and treat the puppy as soon as doody is done. Display dissatisfaction when doody is done inside house. Prevention is better than cure. Every hour (you will get a 'feel' or when the time is right) take dog outside to potty. Teach the dog the 'potty' command, if you think they should.
If they sleep inside the house, get a cage/box that is made comfy, big enough for dog to easily turn around in, but small enough that it can't potty in cage's corner and go back to the other corner to sleep. Dogs don't like to do that where they sleep, if the space is not too big. This is not abusive to a dog, they actually like the comfort of knowing the confines of space. If the dog wants to go potty in the middle of the night (will happen two or three times) the dog will start whining. Take dog to potty outside. Praise again, make it a positive experience to potty on grass. Keep 'cage' next to your bed. This is just an idea.
Sorry if this comes off as slightly intimidating, but I have seen too many families with unrealistic expectations of what they think it will be like with a new puppy, only for it to be 'sent back' because they can't deal with the frustration. They did not care to learn. It sickens me, because this innocent being has now probably been deprived of the most productive training time with a good family, and it will be harder to find a good home, after the adorable puppy stage, who will want to deal with a (rightfully so) frustrated and anxious dog.
But eventually, all the effort definitely pays off. Lots of fun and amazing memories together. A fuller, richer life for both dog and humans. It is totally worth it.