You can provide ordinances for your ancestors and others in the spirit world by attending the temple yourself. Doing so blesses you as well as those you serve. . . .
Attend the temple as often as possible. If you have not yet identified ancestors in need of ordinances, perhaps members of your ward need help in providing ordinances for their ancestors. Also, the temple can provide you with names of deceased individuals for whom ordinances need to be performed. If distance and cost of travel make temple attendance difficult, go to the temple as regularly as possible.- A Members' Guide to Temple
and Family History Work, p. 5