As long as statutes are written there will be two truths which require judicial decisions. First, there will be ambiguities written into the statutes/constitutions (textual ambiguity). Second, circumstances will arise which may, or may not, fall under a particular statute or constitutional clause (situational ambiguity). It follows that, if we are to be consistent, once a judicial decision has been made clearing up the difficulty this interpretation of the law should be universal and constant (so long as the decision is appropriate to the language of the pertinent statute/constitution1).
 The best method of interpreting a statute is to use textual interpretation doctrines such as the Rule of Lenity (in criminal cases), expresio unius est exclusio alterius, noscitur a sociis, or ejusdem generis. This type of interpretation gives the most honest reading of a statute.
 In the few cases when the meaning of a statute/constitutional provision cannot be determined textually, historical meaning and legislative meaning analyses should be the next step. Historical meaning would look toward dictionaries or writings of a particular time to determine the meaning of the ambiguous word or phrase. Legislative meaning would primarily look toward other statutes with similar phrasing to clear up the ambiguous wording.
 If this fails, the next step is historical intent or legislative intent. This is the point at which interpretative tools become shaky. Historical intent is notorious because it's often one sided and/or incomplete. No one knows what every single member of the constitutional convention intended and it's unlikely that any historical analysis has proven what even a majority of them intended. Legislative intent suffers the same flaw; it's near impossible to prove what a majority of Congress thought about a statute passed as part of a two hundred page omnibus bill.
 In the very few cases which get through all the above, there's the appeal to other authority. In the past this might have been to the Great Thinkers: The Philosopher, Aquinas, Maimonides, Averroes, Hume, Kant, Locke, Burke &cetera. In modern times this is more likely to take the form of decisions by foreign courts. While both of these can shore up a decision, they are the shakiest form of interpretation. This is primarily because they do not have any anchors in the American legal system. We should always be suspicious that these sources are appealed to because American jurisprudence leans the other way and some source is needed to allow the judge to reach the conclusion he wants to reach. After all, how many people in modern times receive an education to the level that they even know who Averroes was, much less can quote his philosophy? And, why would an American judge know about an opinion published in Australia 7 years ago?2
Personally, I'd like to see a lot less appeal to authority in our courts. Beyond steps  and  above, it all looks like the judge has come to a decision and is just looking for justification. Assuming a previously unresolved ambiguity, it should be perfectly acceptable to state that ambiguity, state why the ambiguity cannot be cleared up by  and , and then set out the court's decision. If it is consistent with statute then good precedent has been set.3
1 The great flaw of deference is when it reaches a near mystical level and is slavishly followed no matter how out of touch a decision may be with the actual language of a statute.
2 The Australian Supreme Court could publish the most amazing, insightful, breath-takingly wonderful piece of reasoning on the right to free speech tomorrow and I might, MIGHT, find out about it because I get ABC's feed on my Twitter account. It's not exactly easy to research case law from another country.
3 Yes, I know this will never happen. Lawyers are mistaught from their first day in law school to over-cite, to always have a source. Original, uncopied thought is the bugaboo we are all taught to fear.