If you are using ancestry try using wild cards * to cover any variations in spelling eg Wilf*d so Wilfred and Wilfrid will come up or just put Wil* or Wilf* The same for surnames Clark* will bring up Clarke/ Clarkson etc. You can put them at the beginning also just in case someone's fancy writing has turned an L into an S or something eg *ever will get you Lever/Sever/Dever. I use the old search on ancestry as I find it more user friendly but I do go to the individual data bases (RH side of page) because not all results in all data bases appear when using the general search. Having said that I have found using the old search on ancestry that I only get 1911 results when I use the general search (probably me doing something wrong)
On FreeBMD if looking for a marriage using the names of both bride and groom and not getting any result try using just the first name of the bride or just the name of one of the parties. This will allow for any mistransciptions due to illegible entries. Also for births after 1911 you can use the maiden name of the mother to narrow down the possibilities.
On famiysearch.org wildcards aren't necessary as it brings up its own variations.
Also The National Archives at
http://www.nationalarchives.gov.uk/ It can be a bit of a maze to navigate but is worth persevering for Wills, divorces etc.
And of course just reading the threads on Rootschat where others give links to sites which they find useful.
As to whether it is the correct info sometimes it is a process of eliminating the pieces of information and trying to confirm what is left. Sometimes successful, sometimes not.
Always make a note of where and when you found/received the information and keep reference numbers such as those for the censuses.