Is anyone familiar with a comprehensive source (a book or a web-site) for techniques used in evaluating the limits of functions ?
You can try: http://planetmath.org/ListOfCommonLimits.html
The bottom of the list also includes a textbook source that is helpful for limits:
Catherine Roberts & Ray McLenaghan, ``Continuous Mathematics'' in Standard Mathematical Tables and Formulae ed. Daniel Zwillinger. Boca Raton: CRC Press (1996): 333, 5.1 Differential Calculus