Procreate is an extraordinarily powerful art app that enables you to do so many things on your iPad. Beneath a deceptively simple interface lies a very significant degree of sophistication and capability including significant flexibility and ease to layering and transformation functions. It is highly responsive to the Apple Pencil. App2Art now uses Procreate more than any other art app. http://itunes.apple.com/gb/app/procreate-sketch-paint-create./id425073498?mt=8

There is an extremely comprehensive and well laid out instruction book free to download on iTunes. https://itunes.apple.com/gb/book/procreate-artists-handbook/id520694987?mt=11

If you want an art app that dispenses with digital complications (such as layering) and instead performs as a very slick facsimile for traditional media then Art Set may be the app for you. The interface creates a user sensation very similar to that found with original materials. So this app is well worth playing with. Currently, we would prefer Artrage, despite its occasional issues with stability, because it offers so much more in the way of customisable and creative options. But Art Set is an elegant and attractive art app which may resonate with some artists. https://itunes.apple.com/gb/app/art-set/id469918702?mt=8

Sketch Club has a rich diversity of pencil and brush effects as well as a range of other great tools with some really nice textures. So if you want nice tonal quality but in an app with layers give Sketch Club a go. A lot of the portraits in the Galleries have been completed using this app. If you are using an Apple Pencil experiment with some of the brushes because some are superbly responsive. http://itunes.apple.com/gb/app/sketch-club/id404414176?mt=8

Artrage is the still best digital facsimile for traditional media, but relative to an app like Procreate, it is slightly less stable. If it freezes on you then just close it out of your operating memory (double click on home button and then shut app) and re-open the app afresh. Well worth persevering with. Artrage has recently launched an Android capable version too. http://itunes.apple.com/gb/app/artrage/id391432693?mt=8

A tour through some of the key Artrage functions https://www.artrage.com/artrage-ipad/features/

Artstudio is a very versatile and capable iPad art application. In terms of App2Art's personal preferences it only marginally lags the likes of Procreate and Artrage. But Procreate does not currently offer an iPhone/iTouch version and Artrage's iPhone app has significantly reduced functionality relative to its iPad version. By contrast ArtStudio's iPhone app is enormously powerful. So at the moment if we had to recommend our top pick for iPhone art it would be ArtStudio. http://itunes.apple.com/gb/app/artstudio-for-ipad-draw-paint/id364017607?mt=8

A "how to" pdf tutorial http://www.luckyclan.com/artstudio_manual.pdf

Asketch is quirky but creates superb tonal values and highlights. The app also delivers a common platform across both the iPad, iPhone/iTouch. It is the closest thing we have found to digital charcoal and this makes it a favourite sketching medium - particularly where you want to sketch rapidly and on the move. As a formative art app it is less well suited to the advent of the Apple Pencil than some of the other art apps here. It is brilliant for finger sketches - which is where it all started. We do, however, recommend reading the user tips on the developer's website via the iTunes link, below, when you first familiarise yourself with the app. http://itunes.apple.com/gb/app/asketch/id371723593?mt=8

Link to instructions and FAQ on the developer's website http://akernsoft.com/ASKetch/index.php#help.php