The two most useful practical guides on where to fish are:
"70 Lochs, A Guide to Fishing in South Uist by John Kennedy (available via the Borrowdale Hotel. Tel: 01878 710366) and
"Trout Fishing in Lewis" by Norman Macleod.
A "Fisher in the West", An Experience of Hebridean Angling by Eddie Young, £6.00 (Approx.), is also packed with useful chapters on flies, tackle and the delights of fishing here.
I would also recommend Stan Headley's 'The Loch Fishers Bible' which is an excellent overarching guide to fly fishing in Scottish and Irish lochs.
70 Lochs may be purchased at the Borrowdale Hotel. The Fisher in the West and the Loch Fishers Bible are available via Amazon.