There are good things and bad things about searching a job in Spain. As a foreigner, it may be a bit difficult to find work. There are many people who do not find work immediately, and have to wait for several months before getting employed. Sometimes, in Spain connections play a big part of finding a job, so not knowing anyone can be unsettling. In many cases, the average employee gets less paid than the manager does; there is inequality in the way salaries are spread. However, if you are searching for a job in retail, things are not that complicated. Restaurants hire foreigners; basically, you will have more luck in places in which foreign languages are needed and the customers are mostly foreigners, too.
When you want to send in a resume to a Spanish company, you have to be persistent. Unlike in the US, the Spanish companies do not call back much. After you sent in your resume, do not sit and wait, but call them and be persistent about it. Like previously said, social connections will help you find a job easier. Try and make as many connections as you can; go out and meet people.
When you write your resume, be careful to the way it is formulated. Spanish resumes differ a bit from what you are used to in the US. Education is written first, the schools you attended, etc. When you write a cover letter, make sure it is concise, clear and straight to the point.
The salaries in Spain are not big. Do not expect to be paid like you would be in countries like UK or US. The average paycheck is about 17000 euro. The salaries are paid monthly, and calculated monthly. Bonuses are received about 2 times a year, before the Christmas holidays and before the summer vacation.
The working hours in Spain are a bit different than in the other parts of Europe or US. The lunch break is quite long (about 2.5 hours) and after that, the employees go back to work until maybe eight in the evening. In the recent years though, Spain started adhering to the work schedule of the rest of Europe, with shorter lunch breaks and shorter schedule overall.
The vacation time is about 1 month, and it's provided by law. Usually, people take this month off in the summer. There are also some national holidays which provide free days.
Spain is a lovely place to live in, so do not get discouraged by the work prospects. If you are persistent and good at what you do, you can be sure that sooner or later you will find a job you can be satisfied with.