[header] How to crash a party [title] Dress the part. [step] At a bare minimum you should make yourself clean and presentable. The next step is to wear the appropriate party attire, so that you look the part and don't draw attention to yourself. 
Everyone appreciates a well-dressed party guest, but appropriate attire will depend on the type of party you are trying to crash. [substeps] If it's a house party, go for smart casual.