A DSLR is not cheap, even the entry level models are around £500 so it is important to do your research thoroughly and as a previous poster has said, handle as many different brands and models as you can. Once you have invested in a camera it is likely that over time you will want more lenses, a flash and other accessories so switching brands then becomes very expensive. Make sure you get it right first time as most people then remain loyal to that brand having invested heavily in gear.
Do any of your friends/family have a DSLR? If so try to handle or better still borrow one for a day or two and see how you like it. Read as many reviews as possible but take owner reviews with a pinch of salt as once we have committed to a make we often try to justify it!
As far as DSLRs are concerned there are no poor cameras, just some are better than others at certain tasks. Is build quality really important? Are you likely to be out in all weathers taking photos? Then a weathersealed model with a magnesium alloy body should be considered. The entry level/mid-range models usually have a polycarbonate body and although this is adequate for most people and they are robust enough they may not stand up to rough treatment. bear in mind they are considerably lighter though and more convenient for prolonged use. Some cameras have a multitude of buttons and dials on the body. This is to facilitate easy and fast changes in various settings. Some entry level cameras require you to go into the menu system to make these changes which is slower. Decide which you prefer.
If you are likely to use your camera in poor lighting conditions then you may need one with good high ISO capability. Reviews will point this out. Again some are better than others at noise suppression.
One last point. Some good deals are to be had on camera bodies complete with a lens or double lens kit. Don't turn your nose up at kit lenses. Most are decent quality but obviously not as good as upscale (and usually expensive) optics. If they have any distortion or other issues most can be corrected in software and you will need to invest in an image manipulation programme at some stage, especially if you shoot in RAW format.
Whatever you purchase I wish you well with it and many happy years of use.