This is a great question but it is really tricky to answer! Why? Because what people think is a nice smile varies so much. For some people it is a natural healthy smile with no teeth missing but for others it is more of a super white perfectly symmetrical smile.
For us our main focus initially is that there are no decay, infections, fractures or gum disease... control all of these variables and your dentist will definitely be happy (if there's such a thing!). So just by regularly attending your dental check ups, hygiene sessions and looking after your teeth is a great way to start getting a nicer smile. Make sure you floss daily!!!!
Now some people have crowded teeth that are difficult to clean or are worn down and irregular. These teeth normally could benefit with some teeth straightening orthodontics first. Why because when the teeth are in a balanced, neutral and level position the bite is normally better, the teeth wear at the same rate, they are easier to clean and lastly they look better. We prefer to move teeth than drill them down and place veneers and crowns where possible. Why? Because the more tooth you have left the longer your tooth will last in your mouth... as soon as you drill that's tooth that you will never be able to get or grow back (at this moment in science).
Some people like their teeth with a bit of character and just would like their teeth cleaned or their teeth whitened. Now this is relatively simple and easy process and we would normally recommend this as a starting place to getting what you may perceive as a nicer smile.
Some times the edges of your teeth are worn down or chipped. It is important to understand why these chips or fractures have occurred. Why? Because what stops what we do from chipping and fracturing again in the future - then you will just have a frustrated dentist and patient. Sometimes it is from previous trauma but many times it is due your bite and teeth grinding (I would say at least 60-70% of the patient's I see grind their teeth at night). So you may need a little bit of composite bonding and a night guard made to help with this and protect your teeth.
So this is just part 1 of this blog... in part 2 we will continue with what the options are and how we design what we think is a nicer smile.