when doing u-turn, remember your cornering used in figure 8
course. as the instructors will tell you, you gotta aim for the
centre lane on the other side. suppose if it's a 3 lane road, you
aim to go into the middle lane after you turn. if it's a 2 lane
road, you turn into the left-most one. use either gear 1 or 2, if
you're in 1, clutching is important, as your bike would be jerky if
your control is not there. for gear 2, remember your cornering
skills. as the bike leans, lean in with the bike, and throttle up a
bit if you find that you're too slow (feels like you're going to
fall when you lean in)
for lane changing, follow the steps:
1. check mirrors to see if the lane you're going to is clear.
2. signal right. depending on the traffic condition, and where
you're at, sometimes you may have to signal even before you check
the mirror. one example is after you just turn left into AMK ave 6
from the small road that leads to SSDC.
3. check mirrors again
4. if it's clear, check blind spot
5. when turning in, turn your handlebars slightly towards the lane,
and increase speed, so you filter into the lane smoothly. DO NOT,
turn abruptly by turning too much (immediate failure for changing
lane without due care), or "swing" the bike as you turn in. the
last point is conveyed to me by the instructor. what he meant was
that you shouldn't turn in like you're cornering, keep the bike
upright, turn the bars a bit, and accelerate into the lane. but
take care not to exceed the speed limit. i did this, but luckily
got away with it... 
best of luck! hope the points above help!
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rock hard... ride free...