Here's a few meandering comments. I'm not focusing on the technical side - you can get tons of this kind of help all over the place. Instead, I'm going to focus on the big picture - how to make tracks more professional sounding.

Imagine you're a busy A'n'R guy who gets hundreds of tapes a week, and listen to your track from that perspective. What are the strengths and weaknesses of your track? What is different? What catches the ear? Where does it lose interest? Why? Would you invest money in this artist? If not, why not? If you heard the track on the radio, would you turn it up or turn it off? Be honest. Then work on the areas you are weak on.

Arrangement checklist

Look at the arrangement. Do your tracks have dynamics? Quiet bits, loud bits? Do those dynamics (or lack of them) contribute or take away from the track? Are you accentuating the bits that need to be strong?

Do you have a fixed number of instruments playing all the way through the track, or do you have different instruments and parts playing in different sections? Bringing different parts in and out will help avoid stagnation - many pro recordings can have 60+ tracks, but they are not all playing throughout the whole song - some tracks may only have one sound in one bit of the song.

Do you have hooks - things that the listener can latch onto? Taking Celine D again (Ok, I dislike her voice, but those tracks are fantastically arranged and produced). Those tracks are full of hooks. Aside from the vocal ones, there are little musical hooks all over the place - even a four note repeated phrase in the appropriate place can add personality to a track - as soon as you hear those notes, the listener knows instantly which track it is. Hooks aren't just for pop records - every little thing you do to help the listener and make their four minute experience a ride will contribute to a positive reaction. If you have a *really* excellent sound, riff, musical idea, arrangement or sample, rather than repeating it loads of times, consider using it just once or twice. This will make the listener instinctively want to reach for the rewind button and hear that bit again - and it'll also mean that it takes longer for your audience to get bored of the track. Repetition is a good thing, because it helps people become familiar with the song quickly. It also gets boring quickly - try developing your repetitions by slightly changing it as it repeats.

Do you have a static structure? (ie, intro, verse, chorus, verse, chorus, chorus). Is the arrangement of each section the same each time? Does the second verse sound pretty much identical to the first, apart from different lyrics? Warning: stagnant repetition. Try adding some extra little glossy touches in the second verse - or taking these away from the first verse if they exist already. Are all your sections fixed lengths? (8 bars, 16 bars) Consider playing around with time - often sections have a wasted bar or two before the next section comes in. If it doesn't add anything to the song, lose 'em. Get in the habit of trimming the excess fat. Do you have musical parts that overlap the section boundaries? If not, sometimes tracks can feel as if they are pieced together in sections, rather than a flowing entity.

Does the track feel like it's climbing? Generally, if you stay on the same level throughout the track it will get boring. The listening journey should be a little like a mountain hike - start off on shallow slopes and go upwards, crossing a peak and coming back down to gentler slopes, then going up a bigger mountain, briefly crossing a sharp valley, tackling vertical slopes then emerging at the summit as the king of the world!

Think of the tempo: is this static throughout the whole song, or does it breathe the way real musicians naturally perform? Get a little faster in the choruses and "up" sections, and ease off for the more laid back parts. This can be very subtle, but can make an enormous difference. There are also ways of making the feel of the track slower or faster by what the instruments are doing - for instance, slower, flowing parts will help pull the track down, and short, spiky syncopated parts will help to fool the ear into thinking theres more life and tempo. The rythm tracks will help in a big way - try pulling the drums in the choruses forward a few ticks, so the drums play very slightly earlier than the beat - this again has the tendency to pull the track forward and make it seem like it's "rushing". The reverse is also true - try moving the snare back a few ticks in the verses. This has a dragging effect.

And look at that drum programming if you are sequencing the drums. Are you trying to get a reasonably natural "drummy" feel, or something a little more contempory? Is anyone *really* convinced..? Don't have a drum machine pattern ticking away in the background for the duration of the song. Stagnant repetition again. Look at drum fills between sections - these act like "full stop, new paragraph" markers to help delimit sections, even when quite subtle. You can also accent other parts of the song with drum fills - reinforce that cool little phrase the vocalist does in the second verse with a sympathic fill/accent in the drums (keep it subtle, though, unless you want a big dramatic effect). While we're here, reinforce it with some of the other instruments too - the whole arrangement should feel as one, not like twenty instruments all playing their own parts that happen to fir together more by accident than design!

Vocals

Aside from the obvious stuff (pitching, performance, emotion), look at you vocal arranging, and maybe be a bit more adventurous. The human ear is more attuned to hearing the human voice than any other instrument, so try making more of the vocal parts in a song. Harmonies, counterpoints and doubling can be extremely effective in the right places.

Is your arrangement emphasising the correct parts of the song. Generally, verses are a little laid back, bridges are building towards the high point (chorus) and the chorus should instantly feel like the main part of the song.

None of the points I raise are absolutes - they will vary according to the song and the style of music. And they certainly aren't the only things to bear in mind. But they *are* worth thinking about when you look at your song, especially if you haven't thought about this stuff before.

Arranging is just one aspect of the whole process. All the other parts (songwriting, language, programming, mastering a whole bucketload of musical instruments (and styles), engineering, mixing etc etc). They all have this level of detail, and everything should be working together to produce a really breathtaking result. Now you can see just how much stuff there is to master - and why a combination of talents will almost always result in a better end product (assuming the individuals work together well).

Above all, listen to music, and tune your ear to this stuff - it's all there for the plagiarising! You can learn loads by looking at a successful track and working out just why there's a key change at that particular point, or why the second chorus didn't do the obvious thing, and you can use these ideas in your own music. After all, it's easy to recognise samples from other people's songs, but much harder to recognise arrangement ideas! :)

Everybody's still learning. Some people may be ahead of you, but they may have started earlier, or maybe had a few shortcuts, or perhaps they can sustain a faster pace. Absorb everything you can, and apply it. Sometimes it'll work, other times it won't. But all the time you are building on your experience and developing your talents, and you *will* improve. And that's guaranteed.