This is the manner in which I pray for you:
that your love toward one another would increase more and more in knowledge and insight,
so that the decisions which you make might be "best" for the community.
As a result of acting in this way, you will be perfect and blameless when the Day of Christ dawns,
because you have been filled with the fruit of righteousness which comes by virtue of your connection to Jesus Christ.
Finally, the end result of all this is the glory and praise of God.
(1) Love's foundation. The immediate question which one faces when interpreting 1.9 is to whom the "love" Paul speaks of is directed. The two ostensible options before us are "God" (rd. "love toward God") or "one another" (rd. "love for one another"). As my (hurried) translation above indicates, I think the latter understanding coheres better with the design of the passage. Not only does the phrase which immediately follows support the "love for community" reading (more anon), but there may also be an exegetical cue in how Paul begins this pericope; 1.9 starts with the use of kai ("and"), thus paralleling what follows with what preceded. And what does precede? Paul's confession that he "longs for the believers with the affection of Christ Jesus." Interpersonal love, in short, seems to be both the focus not only of his closing salutation in 1.8, but functions also as the springboard for his prayer in 1.9. To state the matter plainly, the like-Jesus love Paul possesses for the Philippians he now prays that the Philippians will possess (and exhibit) toward one another.
(2) Love's fall-out. In Paul's logic, "love" immediately impacts two domains: "knowledge and insight." And, as these categories develop, so develops also the Philippians' ability to make decisions which better the community. In other words, when believers enact the love of Christ, choices bent on self-preservation, self-advancement, or minimization of others are abolished. (It is not incidental that what Paul prays for now he turns his quill to addressing in full later in the epistle.) But not only is the community built up by so living and acting, they also ensure for themselves shamelessness (via "perfection" and "blamelessness") at the Return of the King. This "blameless and perfect" appearance is, as mentioned, consequent to community love; and yet in vs. 11 Paul uses a participial phrase to clarify more exactly how this will take place. And so he writes: "being filled" or "because you have been filled with the fruit of righteousness..." Again, as my translation suggests, I'm reading this phrase (for the moment) not as a statement regarding "incorporated righteousness" per se, but rather as a consequence of incorporated righteousness. In other words, the "righteousness" speaks of works done because of the morally righteous status of which all believers are recipients via union with the Son. (As Morna Hooker puts it: "Being in Christ means sharing his righteousness: and that means, not simply his status before God--his vindication as the Righteous One--but his moral righteousness.")
(3) Love's aim. The final phrase, while short, is indispensable for Paul: "the glory of God." While the prayer here in Philippians 1 is foundationally about "interpersonal" or "community" love, it is ultimately about God receiving the honor of which is his due (cf. Phil. 2.11c).
Paul's prayer reveals something important about his understanding of the nature/function of the church: it is a glorious thing to "be," but it is no less a glorious--not to mention necessary--thing to "do." Indeed, our worth is measured by whether or not, and the degree to which we have or have not, imitated Him Who Shall Be Proclaimed "Lord over All." And yet, importantly, Philippians 1.9-11 beckons believers towards Jesus' sort of unreserved self-sacrifice only by inference (as we know Paul expands this concept later). It is fitting that Paul introduces this theme in the context of prayer to the Father. So while it must be our fixed ambition to re-enact the Story of Jesus on the world's stage, success in this quest is contingent upon humble dependence on the one who "having begun a good work in [us] will complete it until the Day of Christ."