If you aim to write clear, informative, persuasive English, you should prefer strong verbs to weak verbs. Usually, weak verbs are general and dull, while strong verbs are specific and expressive. By far, the most common weak verbs are to be and to have.
WEAK: “Yet the anti-Clinton right and the anti-Bush left should recognize that Obama sums up the horrors of both administrations.... We have the 1990s hysteria about populist rightwingers helping to bolster the police state. Alongside the fear of American patriots is the Bush-era hysteria toward Muslims and crackdowns on antiwar protesters. It is the perfect storm for both fascism and socialism...” (Boldface added.) (Source.)
STRONG: Yet the anti-Clinton right and the anti-Bush left should recognize that Obama sums up the horrors of both administrations. Clinton fomented the 1990s hysteria about populist rightwingers to bolster the police state; Bush fomented the hysteria toward Muslims and ordered crackdowns on antiwar protesters. Clinton and Bush fostered both fascism and socialism.
The Takeaway: When you fear you have written some weak copy, here’s a quick way to strengthen it: Count the instances of to be and to have. If there are a great many, replace several with strong verbs. In a 1,500-word article, for example, even ten or twelve replacements will make a noticeable difference. As you write or edit, always prefer strong verbs to weak verbs. It will become a habit, and it will improve your writing forever.
A Good Resource: I recommend you read this brief lesson from the writing center of The University of North Carolina at Greensboro. From time to time, re-read it to gauge your progress.