Actually I practice structure and written expression from the Logman book.

Skill 1:  Be sure the sentence ha s a subject and a verb

 A sentence in English must have at least one subject and one verb.

Skill 2:  be careful of objects of prepositions

A preposition is followed by a noun or pronoun that is called an object of the preposition.

If a word is an object of a preposition, it is not the subject.

Skill 3: be careful of the appositives

An appositive is a noun that come before another noun and has the same meaning

An appositive is a noun that come before another noun and is generally set off from the nuoun with commas. If a word is an appositive, it is not the subject. The following appositive structures are both possible in English.

Subject,  +   APP,  +   verb

APP,   +   Subject,  + verb

Skill 4: be careful of present participles

A present participle is the –ing form of the verb. The present participle can be (1) part of the verb or (2) an adjective.

Is part of the verb when it is a accompanied by some form of the verb be.

It is an  adjective when it is not accompanied by some form of the verb be.

Skill 5:  be careful of past participles:

The past participle is the form of the verb that appears with have or be. It often ends in –ed, but there are also a many irregular past participle in English.

A past ´participle is an adjective when it is not accompanied by some form of be or have.