If you are thinking about moving to Spain on a permanent basis, then you may wish to consider employment. The best way to look for employment is in the local papers such as the Costa Blanca News or another good option is sending your CV directly to the companies you are interested in working for.
Spanish employers are generally very accepting of foreign workers and the contract laws are very strict so workers are heavily protected from exploitation. Ensure that you receive an official work contract from your employer and read or translate it carefully. Temporary contracts are for 3, 6 or 9 months, following on from this this employers are obliged to offer a permanent contract.
The wages are generally lower than the UK, however your cost of living in Spain will be far lower and the lifestyle is better. Your employer will take care of paying your national insurance and tax and this will be deducted from your wages. Income tax in Spain is now around the same rate as in the UK.