Go-To Character Building Websites
Pinterest - Great for coming up with ideas, making profiles ect. (example)
Abbreviations.com - Worried about what the initials of your character mean? This site will bring up all acronyms
Fantasy Name Generator - Also has place names, character descriptions, and even riddle generators
Name and Family Tree Generator - The names this site comes up with are pretty generic, but it's great for when you don't want to do all the math involved in creating a family tree.
Random Letter Sequence Generator - This site saves me from my indecisive brain. You can change the number of letters in a sequence and what letters that can be in the sequence. I use this all the time to pick the first letter of names.
Behind the Name.com - I almost all my character names from this site! This site is really great, because of features like random, surname, and history behind the names. You can specify the nationality, time period, gender, and much more when getting a random name. The site will also give you all the diminutives with a name which is how I got the name Tessa from Theresa. I love how the site will go as back as possible with the origins which is why I always spell Perikles with a 'k' instead of a 'c' and can even spell it in Greek (Περικλης).
It's not necessary to pick names for your characters with specific meanings, but it does give you more direction. An example of this is a character from A Figure Skater and A Secret Agent called either Cade, Aiden Bowman, or Stepan Linna.
The first name was just what I originally called him in my head, so there wasn't any particular reason for this name. Aiden Bowman on the other hand was a name that the character decided to call himself making it important that I as the writer didn't make it random. I think that at some point I wanted to make the joke of one of the characters calling him Cayden, but otherwise I just wanted that 'den' ending. Bowman was important, because the character was trying to emulate a British friend (Spencer Simmons) choosing an English name.
Stepan Linna on the other hand was the name his parents gave him, but I also wanted to show that he was different from the rest of his family. Therefore I gave him a Russian name while the rest of his family had Finnish names (Toivo, Edvard, Aarne, and Sidgrid for example). Stepan means crown in Russian which later becomes semi ironic at the end of the story. Linna means castle in Finnish and in many ways the Linna family are a castle in both strength and coldness.
I hope this helps for anyone struggling with creating characters.