photos with my IXUS 90is, please give advice

Hi, just com back from Holiday last week, used my new Ixus 90is.

I'd like some advice with this camera please,

pix below are what I think have come out good,

could I have got better photos or improve on what I have.

Or am i at the limit of what i'll get out of the 90is?

The long exposures needed at night pretty much require you to use a tripod, so that was the right move. It's pretty much essential for the 1/10-1/6 sec. exposures you were using. In general you want to use as fast a shutter speed as you can, or use a tripod, to minimize blur from camera shake or subject motion. More in a bit on your other points.

Setting a high ISO is basically like turning up the volume on your camera's sensor. It amplifies the signal that is captured by your basic exposure. Along with the signal, it will also amplify any "noise" either in the sensor cells or in the circuitry, so you'll get "static" in your pictures. You can also get noise by taking longer exposures, since the longer the sensor is recording data the longer it has to generate this noise. But generally the noise from a long exposure isn't as bad as the noise from using a high ISO. If you look at the sky in your first shot, you can see this noise, even in the reduced size image you can post here.

The flash on any PowerShot isn't real strong; its effective range is somewhere under 6 m. even at a high ISO. So using the flash will only make much difference, in your case, if you're within 4 m. with the camera at a wide angle or 2 if you've zoomed to the telephoto end (the maximum aperture of your lens changes as you zoom and this affects the flash range). If you're not trying to photograph a person or object that's close to you, you're right, turning the flash off is your best move. And if you're photographing lights, or even brightly lit objects, in the dark but want some background detail too, you won't want to use the flash either. The fountain shot is one example of photographing a brightly lit subject where you'd want background detail as well.

Setting the Exposure Compensation (EC) to +2 basically tells the camera to "overexpose" the photo compared to what the meter tells it is "right". Your meter is calibrated to expose a "typical" scene correctly. The typical scene will average out to mid-tones. If you try to take a picture of something with a lot of white in it, the camera will try to make that grey. So you'd use ++ EC to tell the camera to overexpose it and make it white. Similarly, if you're photographing something that's overall dark, the camera will want to make it grey, and you'll use a - EC setting to "underexpose" it and make it darker.

cheers Jon for your help,

so do you think I'm at my limit with camera or could I get more from it with more practice?

this picture below if what I think is the best I can do...

NIGHT TIME preset-setting
1/8 F2.8
exposure +2
ISO 250

I didn't use a tripod, but did rest it on a solid base and put a 2 second shutter self timer.