Do a search for your local Family History Society, contact the nearest and pay them a visit.
Look for a local U3A and see if they have a Family History Group, there will be probably about 60 other interest Groups with the local U3A.
Find your nearest County Archives and if they are handy join them as they often have courses.
Now I am good at spending others hard earned cash & so I suggest subscribing to Ancestry, yes you can do free searches but it is so much easier when you can have easy access to so many resources.
Next its software, if you do subscribe to Ancestry then there is Roots Magic and Family Tree Maker that have an Ancestry sync feature inbuilt into each of them. I find this very useful.
You can have your prime tree within the software and search Ancestry and the other sites from within the software.
At present Ancestry has my prime tree and the software is there as backup.
Once you have gone back to each Great Grandparent or Great Great Grandparent I would then expand your tree sideways with their siblings and bring each one as up to date as you can.
Next up its a DNA test, plus a DNA test for a Maternal Cousin and a Paternal Cousin.
I cannot stress enough that without DNA validating each branch of a family tree said tree is a Genealogical Tree, that is one based on a paper trail. A DNA validated family tree is a Biological Tree where each line is a proven bloodline.
Many of us have a NPE (not parent expexted) in our trees or maybe an illegitimate ancestor made their way into existance and DNA can help solve the mystery.
Certificates are not necessarily correct, I have a Birth Certificate where a Father is George William yet on his Marriage Cert he is listed as John, plus my GGM was illegitimate and her Granddad is listed as her Father on her Marriage Cert.
