Help speed my droid up...?

I've had the motorolla droid 1 for over a year. I know there are much better phones out there now, but i still love this phone and would like to keep it long enough to get a discount on my next one. I dont know much about computers/phones and mine is starting to really slow down. I rooted the phone the other day so that i could tether to laptop and it almost seemed to get even more slow. i've seen apps to make your phone faster but i dont trust them. could anyone gve me some advice on how i can get this thing working like it used to delete apps that i'm not using and i use a task manager, but now i hear that maybe a task manager is a BAD thing? could really use some insigh from the experts here. i dont do a whole lot with the droid. it's one of my work tools... calculator, google maps, some internet, some music and i barely ever use it to tether.

thanks a lot for any help.