So research how to make it less nasty. Check out the Lexer Hack article on wikipedia.
It also helps to familiarize yourself with classical pathological syntax issues for languages like ALGOL-68 (requires 'semantic actions' to parse correctly) and early versions of FORTRAN (identifiers could have intermediate whitespace, which meant that a typo could corrupt the meaning of the program) and figure out how to do parse a language with an Offside Rule (and not all offside rules are created equal; Haskell 98 is very complex). Then look at techniques like scannerless/lexerless parsing (SGLR, PEG, etc.), combinatorial parsing, etc. Understand what mathematical properties of a parser algorithm and a parser generator you should look for to ease your job. Understand why naive user of a parser generator tends to result in slower lexing/parsing than hand-coded ones. Understand why for some applications we might be able to not care. Understand how to embed good error messages in a grammar-based approach vs. hand-coded solution. Understand the notion of unparsers, which, IIRC, are not covered in any of the Dragon Book at all.