Like others have said try to join the skip road at at least 60mph. That way you can speed up to get ahead of a lorry match cars in lane 1 or settle in behind a lorry who can only do 56 ish mph.
When moving out to lane 2 or into lane 2 keep do a quick shoulder check for other cars moving into the same spot.
Lorries often indicate to move lanes sometimes when alongside. Usually this is because it's busy and they are indicating their intention to cars behind not because they haven't seen you. Having said don't hang around next to them if you can avoid it.
Lots of people exceed the speed limit in the outside lane so don't hang around there doing 70mph if you can move in. Speeding drivers get impatient and may undertake you.
Remember that while people will often move over or let you in especially if very busy it is your responsibility to merge safely or give way etc.
When it comes to leaving give yourself time to get over to lane 2. My instructor used to say you are so my just over 1 mile a minute so if the junction is 1 mile away you have a minute to get in the correct lane.
Yes keep left if you can but bear in mind you do not want to be weaving in and out because if it is busy and there's a lorry ahead in lane 1 you might get stuck in lane 1 if traffic behind won't let you out again
Watch out for elephant racing ( lorries slowly overtaking at slow relative speeds ) and get into the outside lane in good time.