My DS is 13 weeks, and it was a real lightbulb moment when I read in Gina Ford that small babies can usually only last about 2 hours awake. Now after about an hour and a half I watch for signs of tiredness (yawns, rubbing eyes) and then whisk him off to his cot. I get him down about 90% of the time for a morning nap and about 60% of the time for a lunchtime nap which suits me - rest of the time he naps in his pram if we're out and about. He sometimes takes an afternoon nap, sometimes doesn't depending on how much sleep he's had at lunchtime.
I find it is much better to put him down awake but tired during the day - putting him down asleep usually meant that he recognised the shift from my comfy arms to his flat big cot and woke up. I use a dummy sometimes during the day to help him drift off (he usually sucks for a minute or two, spits it out and then quickly drifts off) but we don't use it at night (he is fed just before bed at night so I guess he gets his sucking comfort that way)
In the evening, it has been more hit and miss but is getting much better. I'm with Midge on the important of routine - we just doggedly stick to the same routine every night however badly it has gone the night before and he is getting much better at it: big feed, bath and massage with dad, feed again in darkened nursery then put in cot while very sleepy but eyes half open. If he falls asleep in my arms then he will wake when put in his cot so I don't let him get that far. If he cries full-on then I always pick him up quickly and offer more food, but sometimes he just cries intermittently in a tired way and I might just pat his tummy or hum a lullaby, or leave him alone depending on how much he is whimpering. He doesn't whimper for more than 2-3 mins usually now and the last two nights he has gone down first time with just a big sigh and no whimpering at all! I try to get him down by 7.15-7.30 but sometimes if DH is a bit late home then it is closer to 8pm as DH does the bath.
This routine is loosely based on Gina Ford. A lot of my friends swear by her which is why I have the book but I don't have the patience or inclination to use her routine during the day and want my baby to not need a really rigid daytime routine. But the evening routine - feed, bath, feed, bed - works really well for us. My main/only rule at night is that he stays in his nursery - so if he needs singing to, or walking, or cuddling before he'll drift off then we do all that in the darkened nursery. That way he knows it is nighttime and different to daytime naps where I might just bring him back downstairs or put him in the sling if he isn't going down. He seems to have got the hang of the fact that it is nighttime now. So routine is the best thing I can recommend.
BTW, congrats on getting him to go until 7am. My DS did it for 2 weeks on holiday a week or so ago, but is now back to 5am-6am wakening! Grrr...