The main things are lots of eye contact, smiling and physical contact. He needs to experience himself as loveable - so basically needs to see that you are finding joy in his company.
Theraplay activities are designed to reinforce this bond (check out theraplay.org)
Some information from the theraplay website;
"The Theraplay Institute
Wilmette, Illinois
Lullaby: Parent cradles child in arms in such a way that eye contact is fully maintained. Parent sings lullaby to child, inserting, wherever possible, child's name and descriptions of his or her features. Example: "Twinkle, twinkle little star, what a lovely boy you are. Nice brown hair and soft, soft cheeks. Big brown eyes from which you peek. Twinkle, twinkle little star. What a lovely boy you are."
Peek-a-boo with hands, feet, towel, blanket, hood of coat, behind pillow or door.
This little piggy went to market.
What will happen when I push this button: Parent gently presses nose, ear, toe and "beeps," "honks," etc.
"Pop" cheeks: Parent fills own cheeks with air and guides child's hands to push gently on parent's cheeks with fingers to pop out the air, encourage child to fill up cheeks and parent pops. Toes can also be used to pop cheeks.
Patty-cake: can be played with feet too!
Any song or rhyme paired with movement, such as dancing, bouncing, rocking, moving limbs, finger plays. Personalized wording, as in Twinkle above, is preferred. Examples: Rock a bye baby, Patty cake, Itsy bitsy spider, Ride a horsie, The wheels on the bus, Rub a dub dub, I'm gonna get you.
Various experiences with touch and textures: Lotioning, making hand or foot prints in powder, pressing hands or feet into play dough or shaving cream, baby oil for back rub with the child facing you. Be aware of possible sensitivities to odors.
Activities promoting eye contact: parent puts sticker on own nose and helps child pull it off: parent puts cotton ball on nose with a dab of lotion, child blows it off. Blow bubbles in front of child and help him pop with fingers or toes.
Lotion pass: parent puts lotion on nose, passes to child's cheek, helps child pass it back to parent's forehead, rubs lotion on child.
Comb hair with child facing you, commenting on special color, texture, etc.
Tower of hands: Put lotion on parent's and child's hands and make a hand stack, alternating slippery hands. Move from bottom to top and top to bottom.
Pushing over: Parent and child are face to face with child lying on back cradled between parent's legs; parent and child put hands together or child puts feet on parent's shoulders; child pushes parent over (gently) while parent comments on strength. Note: pushes can also be with fingertips, noses, elbows, etc.
Blowing over: blowing mightily, parent "blows over child" encourage child to do same"