smarter minds than mine will probably answer this with much better skill.
Depending on the craft you are in and the establishment you "may" be working for
Generally, you will want to have your pre landing checks done prior to any approach, this lets you concentrate on the approach itself. Gear and flap selection depend again an a/c and company/training schedules. ILS you will generally have gear and first stage flap for the approach and at the minima and visual, select req flap for landing, at this stage finals checks generally done as well. RWY APPR, pretty much the same. NON prec app, can vary depending on factors stated.
Where I work, Prior the IAF, flaps to approach, pitch to 1900(climb setting), passing the initial approach alt gear down.
WHEN YOU HAVE AN ENGINE FAILURE, PERFORMANCE IS COMPROMISED. GET RID OF DRAG, again depending on a/c etc etc this might be flaps up(clean wing) or gear up. If it is gear up the fact that it is now up is a problem as you are trying to land (eventually, and hopefully off that approach), coping with an engine out situation is req. but that done and you flare to land with the resulting metal scaping sound is a bad thing.
hope that helped
One last thing, different a/c will require different techniques, different organisations use different techniques, most will get you on the ground and in the pub

, others may see you not in the pub
