The word like should never be used before a clause.
Example 1 (incorrect usage): It looks like it will rain.
Like should only be used before a noun, as in the following example:
Example 2 (correct usage): The girl looks like her mother.
Take a close look at the two sentences above. Do you see the difference in how they are used? In the first sentence, like is followed by the clause it will rain. In the second sentence, like is followed by her mother. Whenever a subject and verb follow, remember to substitute like with either as though or as if, as illustrated in the final example below.
Example 3 (correct): It looks as if it will rain.