The key word in your post is "recently".
It really does take a lot of time with certain rats. If you got them from a pet store, chances are they are already nervous about being poked and prodded, and the socialisation process is going to be lengthy.
If they seem a little nervous but not like they're going to bite you, instead of waiting for them to come onto your hand (if you have had them longer than say, three weeks), pick them up carefully by supporting their back legs and with one hand firmly but gently around the abdomen. Make them feel safe in your hands. Don't dangle them, they don't like it and it's scary.
Walk around the house with them in your hands (one at a time) and feed them the tastiest treats you can get your hands on. My best-tempered rat, Doris, goes crazy for meat of any kind, and anything even remotely sugary. A drop of tea or a bit of raisin bread will coax her out of anywhere.
When you go to pick them up, don't try to tempt them onto your hand first. If you tempt them onto your hand and then grab them, they will come to recognize the pattern - treat, hand, GRAB. They are extremely clever animals and recognizing patterns is not difficult for them. When you pick them up, move slowly and be gentle, but don't pussyfoot around with trying to coax them. Just pick them up. If they try to wiggle away while you are holding them, walk around. My best-tempered girl is also my most active, and she doesn't like to sit still. Walking around is one thing that keeps her from trying to leap from my hands to the floor.
If they are curious, let them guide you while riding you. When Doris runs to my left shoulder, I extend my left arm and let her run to my hand. Whichever direction she seems to want to go in (as long as it's not down) that's where I take her.
Also, when you have your rats out for exercise, if there is a place they are trying to get to, use your hands to assist them into getting to that place. For example, Doris knows my room very well now as she has had four months free run of it. The only places she doesn't know are places she can't get to. So now, when I notice her trying to get somewhere (trying to leap from my desk to my door knob) I let her use me as a bridge to get wherever she wants to go. After about a month of doing this, she now understands that not only am I trust-worthy, I am useful.
Be careful when carrying them not to let them fall or feel unsupported. If they feel your body is a safe place to be, they will be more inclined to be near you.
Also, if they are not big jumpers and if the weather is nice where you are right now, you can take one of them outside on your shoulder. Wear a jacket with a hood and if it's not too too warm for it, a scarf. The point is giving them somewhere on your person to hide. Don't ever take them out wearing nothing but a t-shirt. You will soon find rats desperately trying to get down the neck of your shirt. Don't make them feel exposed. The outside world is big and scary. Fortunately, it's also fascinating.
When you are outside with them, you will be their anchor. They will stick to you because you smell familiar, you are safe. You are a bit of home.
The important part of that is they need to recognize their new home (your house) as a real home and a safe place. That brings you back to the most important factor in socialisation - time.
Make sure they get lots of time outside the cage. Doris knows me best now because she is so used to being in the same room with me. I spend up to 12 hours in this room doing work, surfing the net, talking to people on the phone, whatever. And she is always in here with me. So she knows me. She knows my moods by the way I move, when it's a good idea to jump on me, etc.
So I'm just going to reiterate again, give it lots of time and give them a chance to show their true personalities.
time, patience, familiarity, comfort, these are the things that make a rat fall in love. 
