I'm in the same boat, was nice and strong while young and let it all go as life went on. Lately I've made some nice gains however, and FWIW they seem to be coming easier then when young. I guess having a bit more patience, planning and knowledge helps. For me 405 (current GOAL) is right around the corner, and I've yet to do any AAS...
The growth principles mentioned definitely helps. If you want to lift big the only way you can do it is by lifting big, eating right and resting.. It's a good read, opened my eyes for sure.
Everyones different but here's what's worked for me, summed up. Find your max, and ease yourself into a work set with roughly 75% of it. Once you get to where you can handle 8 reps with that weight bump up the weight. Of course as you do this your max will go up but don't worry about this just yet. That's where the planning and patience comes in. Don't focus on the max focus on doing the heavy reps clean and to failure. Keep up and log your weights/reps so that you know where to start or continue next workout. If you can handle 4 clean reps this week shoot for 5 next week. Do this for a couple of months and check your max you'll be suprised. I personally also like to throw in high rep/lower weight sets to help me increase my stamina.
Keep in mind that bench is not chest alone. Shoulder workouts will help, so will extra tri work. Dont stick only to flat bench, I like to do a lot of incline and decline too. I can't handle near as much weight with incline but I can usually handle more with decline. So that's a sure sign of my weakness/strength... Also dont forget the dumbbells, and keep a good training partner. I owe a lot to my partner, he keeps me motivated and always pushes me for more.