To like... が　すき

It is easy to like something and to say it!  Just add ga suki after the object that you like:

ねこ　が　すき　です。
neko ga suki desu.
I like cats.
[note: Nouns don't change in number (no s) so it could mean "a cat".  Also note the desu if dropped makes the sentence more casual - "neko ga suki."]