People worry about anchoring (and so they should), particularly if they are from the marina-strewn south of England, and even sometimes from the Clyde. Do not think you can get away with marinas and moorings in this area - you definitely cannot, and indeed should not if you want to make the best of it.
Don't worry too much if you seem to be close to the shore, or indeed a rock that emerges at low water. You do have to be closer in here than on the south and east coasts of England. Just make sure you have not got too much chain out so that if the wind or tide change you don't go aground.
You need a good heavy anchor appropriate to your boat size along with I reckon 60 metres of chain (not rope). I have always used a CQR with no problem, others swear by the Rocna.
Lay out the chain to 3-4 times the depth at high water, and then motor hard back on the anchor to ensure it is well dug in - this is particularly important in places like Canna harbour which is notorious for kelp (but now there are moorings for the faint hearted).
I never use a tripping line for fear it will trip itself, or wrap itself round the prop, and so far so good. Very occasionally I have put out a second anchor but so often by the time I have decided to do this it was too late because it was blowing too hard. Easier to lay out even more chain if there is room to swing.