Bates,
Too often a soft landing is equated with a good landing. The two aren't necessarily the same. Let me give you a few examples.
I used to do tours of the Grand Canyon in Cessna 207's. The 207 is really the same as a Cessna 150 when it comes to landings; they are flown the same way (like most airplanes). One runway we used had a fairly steep downhill grade, and it wasn't uncommon to land there, due to winds. I would flare, and very often be met with a round of applause by the passengers. Then we'd land, with a thunk, and I'd be met by blank stares...the passeners were applauding the smoothness...and we weren't even on the ground, yet. It was really easy to float down hill as the runway dropped away from the airplane, and get the impression that it was a smooth, greased-on landing. It wasn't.
Tonight I did a go-around for traffic (a helicopter), with a circling overhead approach. It was pitch black, landing on a runway that was dimly lit with solar lighting. Visibility wasn't great, due to a lot of dust in the air. The lower visibility, and the dim lights, create an illusion that one is higher and farther from the runway than one really is. I landed, but flared higher than I should have, and upon touchdown, heard the stall warning for just a moment, then the wheels touched. The touchdown was smooth. A crewmember commented "nice job." However, I knew it wasn't nice: the approach wasn't as stable as I'd have liked, I flared higher, ballooned just a little, and settled in a little slower than I should have. It was smooth, alright...but wasn't a good approach or landing.
Smoothness is a good standard to strive for, but a good landing is usually the product of a good approach, and is far more than being smooth.
A good landing arrives at the right place and the right time, and the right place is the point you choose to land on (not where you float, or where you stall-out...but the point you pick to land on). The right time means the airplane lands as you expect it to...you don't arrive with excess speed and float down the runway wondering when the airplane will finally land. A good landing has a consistent power setting and speed on the approach. This doesn't necessarily mean constant...you don't need to have one power setting and one airspeed all the way down, but it needs to be consistent, under control, and within reason. If your approach power and speed are consistent and under your control, putting the airplane where you want it is much easier.
A good landing involves having the long axis of the airplane parallel to the direction of travel. If it's not, you're landing in a crab...or in automotive parlance, you're skidding (not to be confused with slipping and skidding, aeronautical terms). Land straight. Many training airplanes will let you get away with a lot, but be strict. Landing straight is one of the single most important things you can do during a landing. (The other really important thing is stopping your descent before the earth does it for you).
It's easy to pull back a little too much and balloon. If this happens, relax the back pressure a little, don't push forward, and let the airplane settle back to earth. Add a little power if you need to. If it's not going well, or if it's a big ballooning-up, or a bounce that's getting out of hand, then go around. You can always do it again. Don't try to salvage bad landings. They have a strong tendency to get worse.
Imagine taking a lipstick or grease pencil and putting a dot on the windshield in front of you. during your approach to land, this dot should have the same relationship to the landing point you've chosen, throughout the approach. What this means is that as you turn final approach, imagine your landing point in the center of the windscreen. Your dot is just to the left of the numbers, right in the center of them. Half-way down final, the numbers should still be in the same place, right in the middle of your windscreen, with the dot in the same place in relationship to the numbers...all the way down to the point where you begin to "flare" or arrest the descent.
You'll know you're in the right position to land, just about to touch down, when the sight picture out of the cockpit looks about like it did when you taxied, and took off. Just a little bit more nose high.
The secret to landings is practice, practice, practice, and be critical of yourself. Don't hold mistakes against yourself...but learn from them. Don't expect perfection, but strive for it (it is achievable...I've certainly never reached that point, but I have absolute faith it IS achievable, and therefore keep striving to get there).
Experiment. Try different techniques. Try more or less trim. Try different flap settings. Try different airspeeds. Try different approach angles. Get comfortable with the airplane and the approach and landing by experimenting. Don't go crazy with experimentation, but play with it a little; you'll find that soon enough you'll gravitate to what works best for you...and chances are you'll find that everyone around you is doing it the same way.