You can only say 'look for' or 'search for'. 'Look to' can be a rarely used way to say 'look in the direction of', but that has nothing to do with 'look for' except that it uses the base word 'look'. 'Seek' is another word that you can use, although it's not used as often as 'look for' and 'search for'. To seek smth. = To search for smth. = To look for smth. I reckon 'to look for' is the one used most often. 'To search for' means the same thing, although I think people are more likely to use it to describe more formal or large scale searches (ex. The police are searching for a fugitive). As you just saw, 'search' can also be a noun. 'To seek smth' is the least commonly used (at least, I'd bet it is). It doesn't require a preposition. I think people are more likely to use 'seek' in gerunds or where space is limited. 'Search' can take a direct object, in which case the object is the location being searched. Ex. 'The coastguard is searching the water for a missing person.' = 'The coastguard is searching for a missing person in the water.' So you can correctly say "I'm looking for work", "I'm searching for work" and "I'm seeking work" (in order from most natural to least). 'To be looking to do smth' is also a way of saying 'to intend to do smth'. So "I'm looking to work" can mean "I intend to work."

You could say "I am looking for work" or "I am searching for work" To look for and to search for mean the same thing i.e. to be on the watch for. :-)