It can be difficult to find sources that lead you to finding other family members who are in a census (for example). Clues are key, and attaching those sources builds your case on why the profile you are mending, or adding is correct.. Just how you find those sources is also problematic. I use a software on my PC called RootsMagic (it has a free version). The use of software helps us search records such as familysearch where 100,000+ records are available for review and attachment to your tree. Perhaps you have a family member on Ancestry, and it's fine to share and work alongside your relations to build out your tree. No additional subscription is needed. Ancestry has lots of sources to attach, and later reference once you add your new relatives on Wikitree. Hopefully one of your new relations is already on WikiTree, and you can then attach your tree to one of the main branches within WikiTree. This is key, as getting you attached to the main tree, will if you choose to do so, share your DNA so you can review if you in fact match others who claim they are related to your common profiles. DNA is another helpful tool to point you to distant cousins and perhaps you will find a common surname to tell you how this person is related to you. It's a lot of work to find a 3C so stick to a first cousin until you really ready for a 10,000 piece puzzle.
Always site a source when you can. Look on Find-A-Grave to help build out your tree and get yourself connected to the main trunk of WikiTree. It's hard doing this alone, but maybe with a little work, and once attached, a relation on WikiTree will see your work, and be happy to build along side you.
Census records are a great way to find who is in a family and when. You will see lots of mis-spellings as ordinary people went door to door writing down what they heard. Not all had great penmenship or a very good education, but at least we have a record. Marriage records, birth records, Find-A-Grave.. All are great at trying to point you in the right direction, and helping you build your case. A case that can be reviewed by others, not to frustrate you, but help you stay on the rails if a wrong record is leading you to a dead end.
Hope this helps you on your journey.. Enjoy!