A low-key, by-the-numbers guide for wage earners seeking to improve their financial lot through slow but sure investment strategies. Rifenbark should know. During the last 15 years of a career as a West Coast retailing executive, his annual income from outside investments topped his salary by a handsome margin and he retired a millionaire at age 55. Unlike many serf-made marvels, he concentrates on common-sense information, not brilliant insights. Be businesslike, he counsels. To accumulate funds for investment as well as cash reserves, save up to 10 percent of each paycheck. He also recommends careful budgeting of family expenses and a precise, up-to-date definition of financial goals. (Useful forms are included.) While a variety of investment opportunities are covered--stocks, bonds, money-market instruments, options, commodities, and insurance policies--Rifenbark clearly favors residential real estate as the surest route to affluence. In a lengthy discussion, he notes that apartment properties in good locations afford significant tax advantages, plus dependable income and appreciation potential. This bias, however, does not measurably upset the balance of a how-to work that could prove widely valuable for its systematic assessment of investment risks and rewards.