"The idea that great scientists are master practitioners of a special method — a special way which, if followed faithfully, must lead to success, that is, to a discovery — seems to me, mistaken. It is refuted by the fact that some great scientists (such as Max Planck) made only one great discovery; and though they continued in a life devoted to science, and did not stop producing work of considerable merit, they did not repeat their one outstandingly brilliant performance. The phenomenon is not rare, and this shows that their great success was not explicable by their mastery of a method (whether or not its rules are consciously understood or followed unconsciously). This, however, is not to deny that all or most successful scientific activities have something in common: a flair for the important (and soluble) problem; the imagination which produces not one but many competing hypotheses, and, above all, that critical attitude which, alone, might helpfully be described as a “method”: the method of severely criticizing one’s own ideas." Popper, from page 1031 volume 2 Schilpp "The Philosophy of Karl Popper" 1974.
Ian C.Jarvie, as is often mentioned in the Critical Rationalism group, extracted from "The Logic of Scientific Discovery" a set of methodological regulations/norms in his "The Republic of Science: The Emergence of Popper's Social View of Science 1935-1945", 2001. These do not provide a recipe or a technical method for deriving hypotheses but they provide guidance that may increase the fruitfulness of the scientific endeavor. It is by criticism that we learn and such a set of rules is core to the institutional fabric of science. Jarvie has, from Popper, made explicit what is often implicit in the institution. The ethical demands that these place on us spare no one, including "critical rationalists", whatever the latter might be.
(Supreme Rule) "the other rules of scientific procedure must be designed in such a way that they do not protect any statement in science against falsification" (LScD, p. 54).
(R1) "The game of science is, in principle, without end. He who decides one day that scientific statements do not call for any further test, and that they can be regarded as finally verified, retires from the game" (LScD, p. 53).
(R2) "Once a hypothesis has been proposed and tested, and has proved its mettle, it may not be allowed to drop out without 'good reason'" (LScD, p. 53-54).
(R3) "[We] are not to abandon the search for universal laws and for a coherent theoretical system, nor ever give up our attempts to explain causally any kind of event we can describe" (LScD, p. 61).
(R4) "I shall...adopt a rule not to use undefined concepts as if they were implicitly defined" (LScD, p. 75).
(R5) "[O]nly those [auxiliary hypotheses] are acceptable whose introduction does not diminish the degree of falsifiability or testability of the system in question but, on the contrary, increases it" (LScD, p. 83).
(R6) "We shall forbid surreptitious alterations of usage" (LScD, p. 84.)
(R7) "Inter-subjectively testable experiments are either to be accepted, or to be rejected in the light of counter-experiments" (LScD, p. 84).
(R8) "The bare appeal to logical derivations to be discovered in future can be disregarded" (LScD, p. 84).
(R9) "[A]fter having produced some criticism of a rival theory, we should always make a serious attempt to apply this criticism to our own theory" (LScD, p. 85n).
(R10) "[W]e should not accept stray basic statements — i.e. logically disconnected ones — but ... we should accept basic statements in the course of testing theories; or raising searching questions about these theories, to be answered by the acceptance of basic statements" (LScD, p. 106).
(R11) "This makes our methodological rule that those theories should be given preference which can be most severely tested...equivalent to a rule favouring theories with the highest possible empirical content" (LScD, p. 121).
(R12) "I propose that we take the methodological decision never to explain physical effects, i.e. reproducible regularities, as accumulations of accidents" (LScD, p. 199).
(R13) "a rule...which might demand that the agreement between basic statements and the probability estimate should conform to some minimum standard. Thus the rule might draw some arbitrary line and decree that only reasonably representative segments (or reasonably 'fair samples') are 'permitted', while a-typical or non-representative segments are 'forbidden'" (LScD, p. 204).
(R14) "[T]he rule that we should see whether we can simplify or generalise or unify our theories by employing explanatory hypotheses of the type mentioned (that is to say, hypotheses explaining observable effects as summations or integrations of micro events)" (LScD, p. 207).