1. To show the church their location in time, between the two comings of Christ. I find it useful to structure the service around this, moving from remembering to expecting. It doesn't have to be done explicitly or in a big way. I will always choose at least one hymn that is explicitly about the cross and resurrection. Often, to introduce a note of expectation, I will just end the time of intercession by praying for Christ's return. The key thing is that we all be focussed on the Lord Jesus, and I think in a curious way on his absence - he was here, and we look back to it, and he will be here again, and we look forward to it. (Of course, he is here too. But in a different way).
2. To show the church their identity as the overlap of the ages. One of the things that any worship service needs to be helping people to do is process the week they've just had, and one of the things which will certainly have characterised that week for everyone will be sin. We've all sinned. How do we understand that, and how do we deal with it in the context of worship? I think the answer is again to locate the church: to show them that they do not belong to the old creation, despite their sin. But this needs to be balanced by an understanding that we are not yet in the new creation - we still await the redemption of our bodies. To process the week, and yet avoid despair, we need to see that we are both new in Christ and old in ourselves. We are the overlap of the ages. The most obvious way to do this is through a corporate prayer expressing sin, but I think we need to be careful how we frame it. Very often - and I think this is true of the Anglican form - a prayer of confession leaves us feeling that we belong to the old age but would really like to belong to the new. There is not enough emphasis on our changed status in Christ. If we can get that right, the prayer of confession can be an enormously helpful part of our liturgy.
3. To show the church their relationships with Christ their Head, and with the world. We need to be reminded constantly that we are in Christ. We need to be reminded that because we are in Christ we are loved by God. We also need to remember that we stand in the world. This is part of preparing the church for the week they are about to have. We will come into contact with a lot of people, many of whom do not know Christ. How should we live? How should we relate? We remind ourselves, then, that we are intimately tied to the Lord Jesus, and are therefore to be those who do his work through the week. The worship service needs to orient us in two ways - towards Christ, from whom we expect to receive throughout the week, and towards the world, toward which we must be prepared to give throughout the week. Leading intercessory prayer is clearly a big part of this, because it means explicitly invoking Christ's aid for the week ahead. There are songs which can also help to make this point.
All a bit theoretical, and not very coherently expressed, but I'm trying to make sure I'm not just filling time, or warming up for the preacher, or doing what I know people will enjoy...