The way I tend to use DW Fixer (outside of other hero aid) is a playstyle that I have dubbed "weaving".
First turn Fixer lays down a Tool or Style. Doesn't use Bitter Strike. Second Turn you lay down a Tool/Style (whatever you didn't do first turn) so you have 2 cards out. From here look at your hand. If you have more Styles in hand, Bitter Strike and destroy your current Style to play another one next turn. If more Tools, destroy the tool to lay another down next turn. This creates a pattern of weaving fluidly between multiple styles and tools (which is thematically and mechanically satisfying) and you do not require outside help. Of course you can always take advantage of other Hero's extra cards in play which they don't need, or you can easily play and destroy cards like ToolBox or BloodyKnuckles for full effect to buy time to find more cards to weave in and out of.
With weaving, Fixer loses the consistent situational utility and adaptability of his original hero card/playstyle, but gains seriously strong bursts of high damage