this may help,you need to ask yourself a few questions first and then go and visit to see if it matches your expectations.
1. What is your budget and what do you expect and require from that?
i.e. Some areas are more expensive than others,ask yourself what is more important, a detached villa in a cheaper area or an apartment in a more exclusive location.
Spain is no different than the UK in some respects as in you will pay more for a 1 bed Kensington apartment than a 3 bed detached in Oxford.
When you know the answer to your first question search through some websites and see what you can get for your money.
When you have narrowed down which Costa,you can move on.
2.Is it for permanent residence or holiday use?
Here on the Costa Blanca there are very definite divides between the two,if you want people around you (not just for the summer months) schools,shops,amenities,Internet access etc...
This will help you narrow down your area search.
3.Do you speak the language?
Beleive it or not this will determine the area you will feel comfortable with espcially if you have children,you may want a predominant ex pat area,a mix or if you are feeling really adventurous you can be one of the only Foreigners in the Village.
Remember neccesity is the mother of all invention so you should be driven more by your needs.
4.How close do you really want to be to the sea?
A lot of people come to Spain with a vision of waking every morning to the sound of crashing waves and a beatiful blue vista.
The reality is it can be very busy in the summer and dead in the winter,more permanent residence choose to live about 15-30 mins inland,the prices are better,you get a higher yearly occupancy level(neighbours) and you tend to get a better mix of nationalities,e.g i live 15 mins inland and my youngest daughter is only one of three brits in a class of 16.
And of course if you are working you dont get time for dreamy walks along the beach every morning as you are busy getting the kids ready for school and off to work,( normal life).
I could go on and on and some will tell you i generally do but this is a small guide to start your search.
Hope this helps anyone who is starting out...