If "Elemental HERO Neos" is in your Graveyard, use cards like "Swing of Memories", "Silent Doom" or "Soul Resurrection" to return it to the field and then Contact Fuse it with your selected "Neo-Spacian(s)". But remember: if you want to keep your "Neos" Fusion Monster on the field, you should have "Neo Space" or "Instant Neo Space" ready to play.
"Elemental HERO Neos" is the ideal monster to use to "Hero Flash!!", as it is the strongest of the "Elemental HERO" Normal Monsters, and if it is Special Summoned with "Hero Flash!!", it can attack your opponent directly. The cards required to remove for "Hero Flash!!" can be amazing additional support cards (especially "O - Oversoul" and "E - Emergency Call").
Unless you're going to be using "Hero Flash!!" or Normal Monster support cards, you probably shouldn't use "Elemental HERO Neos" in a traditional Fusion-based "Elemental HERO" Deck. "Bladedge" provides more attack and a piercing effect for the same amount of Tributes.
Use "Hero Blast" to destroy a monster on the field while "Elemental HERO Neos" or "Elemental HERO Neos Alius" is in your Graveyard and bring your "E-HERO" back from the Graveyard. Then (in the case of normal "Neos") use the effect of "Elemental HERO Necroshade" to Summon it to the field. If not "Ancient Rules" or "Fake Hero" do an amazing job as well. You can also save "Hero Blast" for the right moment such as when "Kaiser Sea Horse"/"Light Effigy" have survived on the field long enough and your allowed to Tribute Summon.
When the conditions are met, activate "Reverse of Neos", then "Neos Force" and "Neo Space" ("Skyscraper" if an opposing monster still has more ATK). Then "Elemental HERO Neos" will have a minimum of 4800 ATK and a maximum of 5300 ATK.
Using "Hero Flash!!" can result in massive damage for your opponent, and after attacking with "Elemental HERO Neos", you can finish your turn with "Wrath of Neos" to prevent it from destroying itself by returning it to the Deck.
You can protect "Elemental HERO Neos" by using "Marauding Captain" to protect him and use "Mist Body" or a different Equip Spell that makes "Marauding Captain" not able to be destroyed in battle. This also works with "Heart of Clear Water".
You can also Xyz Summon "Daigusto Emeral" using "Prisma", after sending "Neos" to the Graveyard, with another Level 4 monster and use its effect to easily bring "Neos" to the field.
Due to this card needing to be on the field for Contact-Fusion, when it is in your hand, you can use "Hero Counterattack" or "A Hero Emerges" to pull it out with a little luck. Improve your chances by setting field and spells so your opponent will not pick them.
"Champion's Vigilance" can be used in "Neos Beatdown" Deck as it's not so hard to Summon "Neos" using that Deck.
You can use "Justi-Break" when your opponent declares an attack and all monsters on the field will be destroyed except your face-up Attack Position "Elemental HERO Neos".