My best advice is, unless you really need something specific to strive for to make the game fun for you, don't go hunting after a build just yet. It's your first level 70. Have fun with it and experiment to see what gear/skill combinations fit your playstyle, for now. My crusader was my first 70 as well, and I feel like if I had gone after a build too much, it would've killed the fun for me. Instead, I played as usual, using what drops and crafts I got to maximize my stats and work up from there. Once you get to 70, a LOT of gear with a lot of variety opens up to you, you just have to be lucky and get it as a drop or gamble with your blood shards to acquire it. Work around what you have, see what works, change what doesn't. Trial and error is your best friend in this game. (Assuming you aren't playing Hardcore.)
A general tip that all crusaders can follow, though, is that getting pieces from the Akkhan's set should be one of your top priorities. Akarat's Champion should be your best friend to assist your damage dealing once you find a way to utilize it properly. (My own way is in my weapon: every enemy I kill while using AC becomes a Phalanx avatar for 10 seconds. These guys do crazy damage, and once you have an army of them, you're pretty much unbeatable. Now I'm striving for more Akkhan's pieces to get rid of the cooldown so I can have AC up almost constantly, and therefore, have my army up almost constantly.)
It would also help to use one of the two passive skills the Crusader has to up the damage on your mouse skills: I use the one for Justice and Blessed Hammer, since I also have a boost to Lightning damage from a piece of my gear, and those two have the best Lightning runes. And don't forget that if you get a piece of gear that ups the damage on a skill you don't use and know you won't use, you can use the Mystic to enchant it and change that to a skill you DO use. (assuming the other stats are an improvement from what you have)
Other than that: it's pretty much your call. Try to get a good Legendary weapon / Legendary shield with a good passive, get the best gear you can find, and once you get those, you can start working on the specifics of finding gear sets and making or using a build that can get you up into the higher difficulties.
I generally use this site for looking into gear/weapons/etc. Ignore level requirements and specific stats, as I'm fairly sure everything gets scaled up to match your level, if you find it, and, of course, stats differ. Just focus on the passives/set bonuses: http://diablo.somepage.com/popular/items/crusader
I hope this helps! I'm pretty new myself, but more than willing to help you figure it out.