Purposeful and Proper Prayer

The reading from Burroughs this week challenged me and was very helpful in reminding me of what should happen when I go to the Lord in prayer. I like when he says on p. 272 "labor to get your hearts sensible for what you are going for. I am now going to God. For what?" I think many times I am not purposeful when I pray to God. Burrough's statement of how "The glory of God should be the chief matter we are to pray for" (p. 273) was also very good. My question relates to something he says on p. 274: "Spiritual things may be prayed for absolutely, but outward things must be prayed for conditionally." I understand the examples he specifically gives of confession of sin (inward) and health (outward), but what about things that are not so easily distinguished? Can we pray absolutely for our Father to give us our daily bread? Are there outward things that the Lord has promised us that we can pray absolutely for?