There is the full range in Queensland, from bed and breakfasts to youth hostels and five star hotel chains. For mid range, check out Rainforest Grove in Cairns, or Mariners Gables in Trinity Beach. Both have websites which give you a good picture of what is on offer.
Other options include looking at the Youth Hostels Association website, or doing a search using keywords such as 'mid range accommodation + city / region name' or searching directly through a hotel chain you know and trust. Most cities and towns have one or more tourist information centres which provide information on accommodation in their region, although they may favour certain providers over others for a variety of reasons.
Another good option for where to stay is a site like 'Last Minute' which offers deals for last minute travel.
The website Trip Advisor is a good starting point for unbiased information about accommodation, with photos and candid reports from visitors.