What I did is only recruit lords that are upstanding personalities , they like you if you have a lot of honor. So I have like 200 honor, and they all had 50 plus relations with me to begin with. Just keep releasing lords with good relations with you when you capture them, and so then when they show up and wanna join your kingdom some will already have really high relations with you. Then I found that when I granted one a fief, they all sorta seemed to be friends, so their friends would get plus relations with me, when I granted one of them a fief. Also once a week you can have your steward send the letter for plus relations, 15 relations. I find that giving them titles doesn't really do anything, maybe a once plus 5 relations that's it. Its basically a waste of kingdom funds, I did it only cuz I was making like a million extra a week and didn't need the funds cuz I had already done all my research. If your kindgom is losing money, your doing it wrong, or you don't have a town yet perhaps? Once you have at least one town, make sure your relgious unity is 100 percent, or it hurts. Get that high by giving clergy a lot of the power, don't worry eventually they will lose it again, but keep it high till you get relgion unity to 100.
Finally if your married you can throw feasts, which raises a little, also every time you fight in a battle with them, talk afterwards, that will raise it by 1, and I find myself saving them in battles a lot (when you join in and they are losing) that will raise it by quite a bit also, and if he has friends, you get plus relations with them when you talk to them after saving his ass as well.
All that being said, I think if you plan on recruiting more than a few lords, you best be conquoring lands and handing out fiefs to keep them happy, if your kindgom isn't expanding and you have many lords, it's going to be tough. ACtually It is one reason I don't like the minus 5 relations each week, becuase it is sort of forcing me to keep expanding and I don't really want to win the game so fast. I'd rather take my time, but I feel I am pressured to keep taking fiefs to keep their relations up.