assuming that i am practicing/training/playing a good amount of the time, how much should my rating be increasing compared to time? for example, should i be aiming for an increase of 100 a month? three months? longer? (assuming that i'm starting out as a beginner)

obviously it's different for everyone, but i'm wondering what others would consider the average.

I say, focus on the games and let the ratings take care of themselves.

What has helped me:

1) I now take my time to make a move. There is an analysis board and I use it.

2) I note the mistakes I made in previous games and try not to repeat them.

3) I don't worry at all if my rating goes down or doesn't go up as fast as I want.

you should be earning 2.7 rating points per day in year 1 and that decreases by 84% per year assuming a starting point of 1200.

you can roughly triple that to 6.82 if using Chess Mentor.

i'm kidding - i don't know exact numbers ;)

lol erik my rating increased 500 points in 2 months =)

yeah, but it has not changed since... is chess mentor really that great?

sounds credible though,
I think dedication is more important than time. If you'd really be devoted for the first month, great things can happen (like risings of 200+), but from there every point will be harder to gain.

 If you are not finding Chess Mentor to be an advantage then you are probably not doing a lesson that is suited to your level or are not truly spending the time to take it all in.  If you play a level that is too easy then it's pointless, too difficult and it will be way over your head.  I suggest you take some time to consider what you have learned!

...and on the point of ratings/grades:

This can't be predicted because it's based on your skill level, which we can't predict.

I use my rating as just a piece of information. It is only rough feedback on how I am doing.

If my rating does something unexpected, then I try to decide why and use that information to my benefit. Rating increasing? ... Good I will try to keep doing the same things, and chances are it will go down less. When it does go down, I look at my games and see the mistakes I made. Why did I make them, were they uncharacteristic? ... etc. 

Some day you and I may reach our peek. Hopefuly not for a while, but when that does happen ... I hope we are still enjoying ourselves. :-)

You can get very caught up in ratings. I get really annoyed with myself when I work them up a bit, then blunder to a lower rated player and undo all the good work I have done. Such losses are accompanied by much colourful language and me wondering how on earth I managed to blunder in a correspondance game.