A few things that boosts BB's (Lou's) bond.
• Completing deliveries and earning stars (particularly the 3rd and 5th)
• On occassion
likes it when you use Speed Frame lvl2 or Power Frame lvl3 to double jumo from a long run.
• Inside safehouse/private rooms, Check on BB and sooth
to gain a happiness rating
• Use the mirror and take a photo of a funny face for occassional likes.
• Aim for a BB sign someone has planted in the world every hour of gametime.
• Soothing BB when you fall over or a BT upsets them (BTs don't have as extreme effect after 3 and a half stars)
• Plant facilities in places they'll definitely get used (Online likes pleases BB)
• Gaining likes from mail sometimes makes BB happy
• Getting through BB areas stealthily gives 6-10likes
• Sometimes BB likes when you take down a big BB, but if you don't do it quickly enough, you lose more points than you gain.
• Every now and then you may get likes from trading with NPC porters. But that's VERY rare.
• Whenever an NPC gives you likes for planting a facility, ladder or climbing anchor. BB has a chance to become happy from it.
Most of these are purely luck. Completing Sam Orders and getting stations to level 5 really is the best way, Avoiding BT's completely wheb confronted with them is the best way of gaining more likes. Sneaking up on them and using the umbilical cord cutter to send them back to the other world sometimes has a good chance to help with BB's happiness, this also gains you offline likes from the BTs themselves.