"an air-cooled motor was more effective than a witch's broomstick for rapid long-distance transportation"
"effective teaching methods"
"effective steps toward peace"
"made an effective entrance"
"his complaint proved to be effectual in bringing action"
"an efficacious law"

"people who will do nothing unless they get something out of it for themselves are often highly effective persons..."
"effective personnel"
"an efficient secretary"
"the efficient cause of the revolution"

"an effective reprimand"
"a lotion that is effective in cases of prickly heat"

"the law is effective immediately"
"a warranty good for two years"
"the law is already in effect (or in force)"

"a decline in the effective demand"
"confused increased equipment and expenditure with the quantity of effective work done"

"the fort was held by about 100 effective soldiers"