It may depend on your state, but this is definitely a dicey area. True, patent agents are not lawyers yet are permitted to prepare patents. And what you are proposing may not be more than what a patent agent would do. But it is important to note that although they may be non-lawyers, patent agents are licensed by the federal government, which it appears you are not. While I think I see where MYK's coming from*, I believe you would nevertheless be at risk for your local bar agreeing with blakesq's assessment of the situation.
See, for example, Oregon State Bar v. Ortiz, 77 Ore. App. 532, 534 (1986). In that case a non-attorney had a business helping people prepare immigration visa and citizenship applications. The state bar issued an injunction against him. He claimed that federal law permitted laypeople to help in certain circumstances and so had preempted the state law on the matter. The Oregon Court of Appeals held that he was doing more than what was permitted by federal law and that therefore the state law controlled, concluding that he was engaged in the unauthorized practice of law (relying on the example of a NY patent practice case, in the process):
"The question is whether defendant is immune from state regulation, even though he does not fit within the federal exceptions to the attorney requirement. An almost identical question has arisen in patent law cases. In People by Lefkowitz v. Lawrence Peska Associates, Inc., 90 Misc 2d 59, 393 NYS2d 650 (1977), the court held that, although New York state does not have jurisdiction to regulate patent attorneys or patent agents who are registered with the Patent Office, the state can control the unlawful practice of law by nonregistered practitioners. The court noted that certain lay people are permitted to prepare patent applications, even though that might constitute the unauthorized practice of law, solely because they have federal authority to do so; however, when they lack that authority, the state can regulate their unauthorized practice. 90 Misc 2d at 62. In In Re Amalgamated Development Co., Inc., 375 A2d 494 (DC Ct App), cert den 434 U.S. 924 (1977), the court, after discussing the federal regulations allowing the lay practice of patent law, stated: "[ I ]f the federal government has not granted a license in this area, a state is free to enforce its own licensing regulations." 375 A2d at 497. (Emphasis in original [omitted].) By analogy, because defendant is not authorized by federal law to practice in immigration proceedings, he is subject to state regulation."
And note that attorneys also can run afoul of the law by engaging in "the unauthorized practice of law" if advising in areas in which we're not licensed. Cf. the DC case of In Re Amalgamated Development Co., Inc.:
"An attorney who helps an inventor prepare the inventor’s own application has engaged in the unauthorized practice of law even though the attorney discloses to the inventor that he is not registered to practice before the Patent Office and does not personally file anything with the Patent Office." In Re Amalgamated Development Co., 375 A.2d 494, 189 U.S.P.Q. 192 (D.C. Cir. 1977).
*It seems logical to conclude that since patent agents aren't lawyers yet are permitted to prosecute patents, that patent prosecution doesn't constitute the practice of law. (That was my first reaction.) But that doesn't seem to be how it is treated by the courts. Rather, it seems that the patent prosecutor's role falls within a sub-specialty of law, and that that sub-specialty has a peculiar exemption for those lay people who have proven their expertise within the sub-specialty. So in this view the advising which is part of patent prosecution would constitute the practice of law, but licensed patent agents would be seen to have special permission to advise within that limited area.