So I looked up how to do it my self and found some products on ebay (listed below) and gave it a go my self for a test run before holiday.
Ardell individual lashes - http://www.ebay.co.uk/itm/ARDELL-DURALASH-NATURALS-LASHES-INDIVIDUAL-FLARE-EYELASHES-SPECIAL-OFFER-/201502634001?var=&hash=item2eea7e3011:m:mqCvwVgj9uQOyNvN50rVDgg
Ardell lashtite - http://www.ebay.co.uk/itm/Ardell-LashTite-Eyelash-Lash-Adhesive-Best-Waterproof-Strong-False-Eyelash-Glue-/162265230670?var=&hash=item25c7c2ed4e:m:mHciOp3i5EK_7TkxndZBzrw
So I make sure I have no eyemakeup on what to ever them get my lash on my tweezer and just simpley dip the very end of the eyelash cluster into the eye glue then lay them flat along the lash line.
I put medium sized lashes all along my lash line to create a even look and to make them look full before putting longer ones on to make it look more extrme you could leave it here if you just want them to look super natural but I prefer to have them more longer.
This is my end result as you can see it look a lot thinker now I have put more longer lashes on you can see in the picture I have a slight gap but the laseshes slightly rearrage them self everytime you brush therew them its easy enoguht to fill in the gap
I hope this has been a help and has helped you save a whole load of money ! You can buy eye lash remover from most beauty stores to take them off or just leave them to naturally fall of mine normaly last around 2 weeks making sure I care for them right not getting them wet ! Good luck :).