Wanting to have a web site because many others do is not a good enough reason. Before planning a site you need to ask yourself how your business would benefit from having a presence on the internet. It will depend on the type of business that you have.
As we work mainly with tourism-related businesses let's look at several types of those:

Hotels, studios, apartments, rooms

This is probably the type of business which will benefit most from a web site. The use of the internet for holiday planning is still growing very fast and soon the majority of people will search themselves for their flights and accommodation. This means that hotel owners will need to rely less and less on contracts with tour operators to fill their hotels. This is especially true for owners of small hotels.
If you don't have a web site, you are already loosing money on bookings that you are not getting and you will loose more money in the coming years. But be careful: if your web site is not well-made it will not attract customers. In fact, it might even have a negative effect.

Car rental

This is the second type of business which will benefit enormously from a web site because more and more people shop around for a good, cheap car rental company. But this will only work if your prices are competitive because people will look around for a good deal and it is easy to compare prices on the internet.

The next two categories will have less direct benefits and if they do bring business it will be difficult to know who comes because they saw your web site.

Shops

Most people will walk into a shop because they are passing it and it looks interesting. They will rarely come to your shop because they have seen it on the internet. One exception is if you are offering a product that is special and not easily found elsewhere. Of course having a web site will do no harm and eventually, as the use of the internet becomes universal, having a web site will be as normal as having a shop window. Just don't expect it to increase your sales noticeably.

Cafés and restaurants

In the same way as for shops, most tourists will walk into your café or restaurant because they are there and it looks nice, not because they have seen it on the internet.